Prusa MK4S Review — Is It Worth It in 2026?

The Prusa MK4S arrived in late 2024 as a meaningful upgrade to the MK4, which itself was the long-awaited successor to the legendary MK3S+. Prusa Research has since permanently dropped the price, making the MK4S more competitive than ever. But in a market where Bambu Lab offers enclosed, high-speed printers at lower price points, the question is no longer whether the MK4S is a good printer — it is whether it is good enough to justify its premium.

This is an honest review. The MK4S has genuine strengths that no competitor matches, and it has real weaknesses that cannot be hand-waved away.

Specs at a Glance

| Specification | Prusa MK4S | |--------------|-----------| | Build volume | 250 x 210 x 220 mm | | Max print speed | 600 mm/s (theoretical) | | Max acceleration | 4,000 mm/s² | | Layer resolution | 50 microns (0.05 mm) minimum | | Nozzle | Bondtech CHT (high-flow) | | Extruder | Nextruder (direct drive) | | Bed leveling | Automatic (load cell) | | Filament sensor | Yes | | Power recovery | Yes | | Frame | Open (no enclosure included) | | Connectivity | USB, Wi-Fi, Ethernet | | Firmware | PrusaLink (open-source) | | Kit price | ~$799 | | Assembled price | ~$1,099 | | Multi-material option | MMU3 ($299 kit / $359 assembled) |

According to Tom's Hardware's MK4S review, the MK4S earned an "Editors' Choice" designation for its precision and reliability.

What Changed from MK4 to MK4S

The "S" in MK4S stands for a set of targeted improvements over the original MK4:

1. Bondtech CHT Nozzle

The biggest upgrade. The CHT (Core Heating Technology) nozzle splits the filament into three channels inside the nozzle, dramatically increasing the melt rate. Prusa reports a volumetric flow rate of 24 mm³/s with standard Prusament PLA, a 50% increase over the MK4's 16 mm³/s. This translates directly to faster printing without sacrificing quality.

2. 360-Degree Cooling

The MK4S adds improved part cooling with airflow from multiple directions. Better cooling means better overhangs, sharper bridges, and the ability to maintain quality at higher speeds.

3. Firmware Optimizations

Prusa has refined the motion system firmware, improving acceleration handling and reducing ringing artifacts at higher speeds. The MK4S ships with tuned profiles that take advantage of the hardware improvements.

4. Improved Nextruder

The Nextruder (Prusa's direct drive extruder) received minor mechanical refinements for more consistent filament grip and quieter operation.

Print Quality

This is where the MK4S earns its reputation. The print quality is excellent — consistently among the best in the consumer FDM category.

Detail and Accuracy

At 0.2 mm layer height with the CHT nozzle, the MK4S produces clean, accurate prints with sharp edges and smooth surfaces. Dimensional accuracy is within ±0.1 mm on most test geometries, which is as good as any consumer FDM printer can deliver.

At 0.1 mm layer height, the results are even more impressive, with layer lines barely visible to the naked eye. The 0.05 mm minimum layer height is available but rarely practical — print times become extremely long and the quality improvement over 0.1 mm is minimal.

Overhangs and Bridging

The 360-degree cooling system handles overhangs up to 55–60 degrees without supports on PLA, which is above average. Bridges up to 60–80 mm print cleanly at reduced speed. According to TechRadar's MK4S review, the cooling improvements are one of the most noticeable upgrades over the MK4.

Surface Finish

The MK4S produces consistently smooth surfaces with minimal artifacts. Seam placement is well-handled, and the pressure advance implementation reduces blobs at start/stop points. The textured PEI plate leaves a pleasant matte finish on the first layer.

Speed: Honest Assessment

Prusa advertises a maximum speed of 600 mm/s, but let us be realistic about what that means in practice.

Theoretical vs Real-World Speed

The 600 mm/s figure is the maximum movement speed the printer is capable of, but the MK4S does not print at this speed. Actual print speeds depend on the profile:

• Standard quality profile: 80–120 mm/s outer walls, 200 mm/s infill
• Speed profile: 150–200 mm/s outer walls, 300 mm/s infill
• Draft profile: Up to 250 mm/s where geometry allows

The maximum acceleration of 4,000 mm/s² means the printer rarely reaches its top speed on small models — it accelerates, reaches high speed briefly, then decelerates for the next direction change.

MK4S vs Bambu Lab: Speed Comparison

This is the comparison everyone wants. According to Tom's Hardware's direct comparison, the MK4S with its CHT nozzle is competitive with Bambu Lab printers:

| Metric | Prusa MK4S | Bambu Lab P1S | |--------|-----------|--------------| | Max speed | 600 mm/s | 500 mm/s | | Max acceleration | 4,000 mm/s² | 6,000 mm/s² | | Typical wall speed | 150–200 mm/s | 200–300 mm/s | | Volumetric flow | 24 mm³/s | ~28 mm³/s | | Benchy time (speed mode) | ~18–22 min | ~16–18 min |

The Bambu Lab P1S is generally faster in practice due to higher acceleration, despite the MK4S having a higher theoretical top speed. The acceleration matters more than peak velocity on typical-sized models because the printer spends most of its time accelerating and decelerating, not cruising at top speed.

That said, the MK4S closes the gap significantly compared to the original MK4, and the print quality at high speed is competitive with or slightly better than the P1S.

Material Compatibility

The MK4S handles a wide range of materials:

| Material | Compatibility | Notes | |----------|-------------|-------| | PLA | Excellent | Perfect results out of the box | | PETG | Excellent | Textured PEI plate recommended | | ABS | Good (with enclosure) | Open frame is a limitation | | ASA | Good (with enclosure) | Same limitation as ABS | | TPU | Excellent | Direct drive handles flexible well | | Nylon (PA) | Good (with enclosure and dry box) | Warps without enclosure | | PC | Fair (with enclosure) | High temp materials push the limits | | PVA (soluble) | Excellent | With MMU3 for soluble supports |

The open frame is the main limitation for high-temperature materials. ABS and ASA are printable but benefit significantly from an aftermarket enclosure. Bambu Lab's enclosed P1S and P2S have an inherent advantage here.

The Open-Source Advantage

This is the Prusa MK4S's most underrated strength. Everything about the printer is open-source:

• Firmware: Fully open, community-contributed, forkable
• Hardware: CAD files, schematics, and BOMs are public
• Slicer: PrusaSlicer is open-source and actively developed
• Repair: Every part is available individually, with detailed repair guides

This means:

1. Longevity: Even if Prusa Research disappeared tomorrow, the community could maintain the printer indefinitely.
2. Repairability: You can fix anything yourself with documented parts and procedures.
3. Modification: The community creates and shares modifications, upgrades, and improvements.
4. No vendor lock-in: Use any filament, any slicer, any firmware modification you want.

Compare this to Bambu Lab, which uses proprietary firmware, does not publish hardware designs, and integrates RFID-based filament identification. The Bambu ecosystem is convenient but closed.

As Prusa's MK4S blog post discusses, the open-source philosophy extends to the printer's entire lifecycle, including the permanent price drop that makes the platform more accessible.

Pricing and Value

Current Prices (2026)

| Configuration | Price | |--------------|-------| | MK4S Kit (DIY assembly) | ~$799 | | MK4S Assembled | ~$1,099 | | MK4S Kit + MMU3 Kit | ~$1,098 | | MK4S Assembled + MMU3 Assembled | ~$1,458 | | Upgrade from MK4 to MK4S | ~$99 (nozzle + cooling upgrade) |

Price Comparison with Competitors

| Printer | Price | Enclosed | Multi-Material | |---------|-------|----------|---------------| | Prusa MK4S (kit) | $799 | No | MMU3 ($299 extra) | | Prusa MK4S (assembled) | $1,099 | No | MMU3 ($359 extra) | | Bambu Lab A1 | $350 | No | AMS Lite ($160 extra) | | Bambu Lab P1S | $500 | Yes | AMS 2 Pro ($299 extra) | | Bambu Lab P2S Combo | $799 | Yes | AMS 2 Pro included |

The pricing gap is real. A Bambu Lab P2S Combo at $799 gives you an enclosed printer with an AMS for multi-color — the same price as the MK4S kit without an enclosure or multi-material. The MK4S assembled at $1,099 is more than double the price of a Bambu Lab P1S at $500.

Pros

1. Exceptional print quality — among the best in consumer FDM
2. Fully open-source — firmware, hardware, slicer, everything
3. Excellent customer support — Prusa's support team is widely praised
4. Build-it-yourself option — the kit teaches you how your printer works
5. Long-term support — Prusa has a track record of supporting printers for 5+ years
6. Upgrade path — MK4 to MK4S upgrade is cheap; MMU3 adds multi-material
7. Material flexibility — handles everything from PLA to TPU to Nylon
8. Nextruder direct drive — reliable, handles flexible filament well
9. Community — massive, helpful community and modification ecosystem

Cons

1. Expensive — significantly more than comparable Bambu Lab printers
2. Open frame — no enclosure for ABS/ASA without aftermarket additions
3. Slower than Bambu — in practice, the P1S and P2S are faster
4. Kit assembly takes 8–12 hours — rewarding but time-consuming
5. No built-in camera — Bambu Lab printers include a camera for remote monitoring
6. Wi-Fi setup can be finicky — PrusaLink is less polished than BambuStudio's network features
7. Smaller build volume — 250 x 210 x 220 mm vs 256 x 256 x 256 mm on Bambu

Who Should Buy the MK4S

Buy the MK4S if:

• Open source matters to you. If you care about repairability, modifiability, and avoiding vendor lock-in, the MK4S is the clear choice.
• You want to learn. Building the kit and understanding how every component works is educational and rewarding.
• You value long-term support. Prusa has supported the MK3 family for over 7 years. They have the strongest track record of any consumer 3D printer company.
• Print quality is your priority. The MK4S produces slightly cleaner prints than most competitors at equivalent speeds.
• You are upgrading from MK3/MK3S+. The upgrade path is straightforward and cost-effective.

Skip the MK4S if:

• Budget is the primary concern. The Bambu Lab A1 at $350 or P1S at $500 deliver similar quality for significantly less money.
• You need an enclosed printer. For ABS, ASA, and high-temp materials, an enclosed Bambu Lab P1S or P2S is a better starting point.
• Speed is your top priority. Bambu Lab printers are faster in practice.
• You want the easiest possible setup. Bambu Lab printers are plug-and-play. The MK4S assembled works well out of the box, but the kit requires a day of assembly.

Verdict

The Prusa MK4S is an excellent 3D printer that produces outstanding results. The CHT nozzle upgrade closes the speed gap with Bambu Lab, and the open-source ecosystem remains unmatched. The permanent price drop to $799 for the kit makes it more competitive than it has ever been.

But it is not the best value in 2026. Bambu Lab offers enclosed printers with multi-material systems at lower prices, faster print speeds, and more out-of-the-box convenience. The MK4S wins on principle (open source, repairability, community) and on subtle quality advantages that matter to experienced users.

If you are choosing your first printer purely on specs and price, the Bambu Lab P1S or P2S Combo is hard to beat. If you are choosing a printer to own for 5+ years, to modify, to repair, and to be part of a community that shares your values about open hardware — the MK4S is worth every dollar.

Find models to test your MK4S on 3DSearch, where you can search across all major model repositories to find designs that push your printer's capabilities.

Happy printing!