Prusa MK4S — Review
Published · Researched 2026-09-21
The MK4S is the printer you buy when you're done shopping for printers. Not because it's the cheapest or the fastest, but because it's the one you'll still be running in five years — and you'll be able to fix it yourself when something wears out. In 2026 that pitch is under more pressure than ever, and the honest review has to say so.
It's the current version of Prusa's classic i3 bed-slinger, announced August 2024, and the pitch hasn't changed in a decade: open-source everything, every part individually replaceable, validated on Prusa's own 700-machine print farm in Prague. The S revision added a 360° turbine-fan cooling setup (Prusa claims 75° overhangs without supports), a high-flow brass CHT nozzle as standard, input shaping, and a little GPIO "hackerboard" for tinkerers. You can buy it assembled for $999 or as a kit for $729 — and a lot of people choose the kit, which tells you something about the audience.
What's genuinely good starts with the thing reviewers keep circling: it just works, and it keeps working. One Facebook owner reported 18 months of daily printing with nothing but routine lubrication. Tom's Hardware gave it Editor's Choice and called it the best machine a beginner could start on; TechRadar scored its print quality a perfect 30 out of 30; CNET named it the best printer for quality. The long-term evidence got stronger this research pass: Tom's Hardware's long-term retest found the original MK4 logging over a year of near-constant printing with "little attention", and Prusa's 2025 anniversary roundup cites farm operators reporting 30,000+ hours on MK4-family machines. A mini-farm owner (March 2026) describes early first-layer and PLA top-surface rippling issues resolved, and emphasizes the key maintenance discipline: keep the nozzle and load-cell contact clean. The kit instructions are famously excellent — color-coded, step by step — and the printer self-calibrates after you build it, validating your own assembly work. When something does go wrong, Prusa's 24/7 live chat is the support experience other companies get compared against, and every spare part is sold individually in the E-shop — or you can just print the plastic parts yourself, because the farm does. The open-source firmware means the community can actually fix and improve things, not just file tickets. The owner discount program (10% off filaments yearly) is a quiet perk nobody else offers.
What's actually wrong is mostly about money, time, and the calendar saying 2026. An assembled MK4S costs $999. A Bambu P1S — enclosed, CoreXY, fast out of the box — streets at ~$399. That's not a small gap; it's a different universe of value, and the community says so out loud. The kit saves you $270 but costs 10 to 13 hours of your life — plus the occasional QC miss like a missing tension band. The recurring 2026 complaints, each with multiple independent mentions: weak, unreliable Wi-Fi — the most repeated current gripe, with dropped connections, DHCP/static-IP oddities, and PrusaLink progress bugs; the community fix is wired Ethernet or a dedicated access point, and Prusa hasn't fully resolved it in firmware. No camera at this price — the community answer is a $30 USB camera plus OctoPrint or PrusaLink, but out of the box it's missing. Open frame means material limits — ABS and ASA want the enclosure add-on or a Core One; the A1 has the same limit, but the P1S doesn't. The kit build is 10–13 hours — not a failure mode, but the number-one buyer's-remorse driver for people who wanted an appliance. Slower than CoreXY rivals — the bed-slinger architecture is honest about its speed ceiling; the MK4S doesn't pretend otherwise. There's no enclosure included (you'll want the official one for ABS, ASA, or PC), and the MMU3 multi-material unit is the weak link next to Bambu's AMS: 25–35 seconds per filament change, five colors max, and Prusa itself tells you to use the standard nozzle instead of the high-flow one with it. One long-time Prusa owner reported a support saga over a Core One that ended with him unable to recommend the brand — different machine, but worth knowing even Prusa support has limits. ByteReview's aggregation of 60 owner reviews sits at 4.3 stars, with the 1-star accounts mostly about first-boot and kit QC issues.
The 2026 problem the spec sheet can't fix is the Core One. Prusa's own enclosed CoreXY (~$949 kit) is now the direct answer to "I want Prusa reliability with an enclosure," and the liveliest community debate — "are there advantages to the MK4S over the Core One for hobby users?" — is Prusa's lineup competing with itself. The MK4S's remaining moat is lower price, simpler maintenance, and the bigger mod community. If you want an enclosure and you're buying Prusa anyway, the Core One deserves a long look before the MK4S.
The social pulse is a culture as much as a product. The 46,000-member Prusa i3 owners group is kit builds, mods, and long technical threads — the opposite of Bambu's show-and-tell feed. The affection is for a company, not a launch: open-source repairability, parts availability, upgrade paths, and a support culture. Nobody's astroturfing here. But the cost counterpoint follows every reliability thread like a shadow — the community loves the machine and winces at the price, both at once.
The value call: at $729/$999, the MK4S is the expensive-but-rational choice, and the defense is entirely non-spec — open-source, repairable in 10 years, Prusa answers the phone, parts will exist. Buyers who don't value that should not buy it, because the P1S at ~$399 gives you an enclosed workhorse with multi-color for less than half the assembled price. Build the kit if you enjoy building; buy assembled if your time has a price. And if you want the enclosure, price the Core One before you commit to the MK4S — the internal fork is real.
The tradeoff, in the community's own terms: Bambu sells you a printer; Prusa sells you the ability to never need another one. In 2026, that ability costs $999, takes 13 hours to assemble, and still doesn't include Wi-Fi that stays connected.