Which Printer to choose (2nd hand Mk3 vs Mk4s)  

The Mk4 is faster and has a few additional user-convenience functions but don't expect significantly higher print quality; effectively the limiting factors are basic physics and even the even older Mk2 gets within a couple of percent of the ideal.  Good prints from all (well maintained) I3 series printers are indistinguishable.

If you buy it, don't attempt to use the MMU until you have at least six months experience with the vanilla printer.  Again, good prints from both MMU2 and MMU3 are indistinguishable but in ths case the MMU3 is very much easier to use.

You don't know how well they have been looked after so ask to see them working before you buy and review a few older threads on here.  I now have an XL but although my old Mk3 is approaching 7 years old and has been worked hard I still use it for some prints.

Cheerio,

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

If you want a tool then get MK4.

If you want a project then get the other printer and waste time/learn instead of printing.

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

Posted by: @toshi

i am  new to 3D printing and I have never owned a printer before.

I could get a used i3 Mk3 (without S/+) with MMU2 for a reasonable price... or buy a new Mk4.

What do you think? Is the Mk4 primarily faster and the Mk3 less precise so that I would quickly regret chosing the older model? 

I would get the MK4S but not just because it's faster and more precise. The MK4S load-cell bed-levelling is the best feature ever. I wouldn't even consider buying a printer without load-cell bed-levelling. 

You can get a load-cell by starting with an MK3 and upgrading to the MK3.9S, but that's additional expense and effort. The MK3 was a great printer for its time, but  that time was 7 years ago. 

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

If budget is a priority and you’re okay with a potentially steeper learning curve, the Mk3 with MMU2 could be a solid choice. If you want the latest and most user-friendly experience, the Mk4 might be worth the investment.

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

100% the MK4 or MK4s. The auto bed levelling was enough to do it for me, but with all the other advancements as well its a no brainer IMO.....

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

Thanks a lot. How ist the "bed leveling" done on the older MK3 printers?

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

Posted by: @_kaszpir_

If you want a tool then get MK4.

If you want a project then get the other printer and waste time/learn instead of printing.

Thanks for the reply. Why is that? MK3s less reliable? A lot of repairs / adjustments to be expected from an older model?

RE:

MMU2 never worked well for me until I did many upgrades.  The MMU3 covered all these fixes.  

I had an MK3S+ I was going to keep using after getting an MK4.   A month later it became an MK3.9 and now is going to be a full MK4S with servo upgrades.

MK4S, Enjoy printing, not so much tinkering. 

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

mk3's used an inductive sensor to set the extruder a safe distance above the build plate, then the user used the first layer calibration tool from the LCD menu (or a preferred alternative, ) to set the actual ideal extruder height, using 'Live Z adjust'
this has been replaced by a load cell above the nozzle, sensing contact between the nozzle and the build plate on the mk3.9, mk4 , mk4S and the prusa XL series printers

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

Posted by: @toshi

Thanks a lot. How ist the "bed leveling" done on the older MK3 printers?

@JoanTabb gave a very good explanation of how is done on the oldest MK3S but to simplify it a bit, In the i3 you had to perform some manual "work" to adjust for the first layer while in mk4 is done by the printer. I don't have an MK4 i went from MK3S/MMU2S to 5th XL but it uses the same load cell method and honestly i would want to go back to the first layer adjustments. Also there is something else which for me makes a difference. I come from a hot summer climate. The way the extruder was designed on the MK3S was prone to heat creep. Basically if the motor was running a bit hot the filament would soften and the extrusion would stop, especially with a .25 nozzle. I bought a bondtech geared extruder to handle this problem. The new extruder doesn't have this problem. Also the removal of the pfte plastic tubes before the heatbrake is another big improvement in my humble opinion. Last but not least why go for an older model if you can go for a newer one?

RE: Which Printer to choose (2nd hand Mk3 vs Mk4s)

New MK4S will be just working out of the box, if preassembled version is bought (or at least assembly is very quick in minutes and not hours in kit version, which makes it easier to make errors and thus getting more frustrated that it does not work for the price you know the printer internals better).

Older MK3 will need some extra work such as basic maintenance to see if it works as it should (assuming someone was aware what was doing it's just a matter of removing some dust, lubricating here and there and tightening some screws.
Older MK3 with MMU2 will need more work, especially when upgrade to MMU3 is REALLY recommended - and this means more time/extra expenses.

Going for MK3 +MMU2 will be a jump on a deep water and you may need to spend much more time and money to finally get the satisfying result.
So for a fresh start for someone never having experience with a 3d printers getting MK4 will be just better experience.
If you need multi-material then you can buy later an upgrade for MK4.

Personally I have Prusa Mini+ for over a year and a half now and it was my first printer.
Ater about 6 months was ready for a bit bigger printer such as MK4.
Do I need MMU? Not really, mainly because I use it for basic functional/technical stuff like electronics enclosure and not minifigures.