it is difficult as many of the specs are not anything particularly detailed.
the SD 4 has a decent extruder set up . the Z axis is a nema 17 motor. and the bed moves in the Z axis only.
x and y are powered by nema 14s.
Falcon, any major calibration or repair issues with your S4?
Major issues no. the usual I added a glass plate and had to level the bed adjust z height tighten belts lube guide rods etc.
I expect one has to do the same with any printer in the similar price range.
Seems that everyone with a 3d printer has their eye on a new printer? What would you get if you were going to buy a new one?
One of the first ones I had my eye on was the plastic scribbler. It seems like a nice machine. If I felt comfortable spending $850 the printer shipping and a roll of filament I probably would have gone with the top of the line PS. But I really wanted to spend less than $500 so I ended up with a used SD4.
If you read much here you will find that a ED3 v6 extruder is the preferred hot end for serious printing also PLA needs directed cooling fans. I have a friend that has IIRC three maybe four printers hes uses on a regular basis and a couple more in storage. He pretty much relies on the internal controls and the sd cards. The other nice to have feature is a dual extruder. it allows for dissolveable support or a second color.
If you have a spare $2500 the ultimakers are great machines. But I would have to be making money with it to justify that kind of outlay.
I have also heard good things about the delta style machines.
And I have pondered looking for a deal on a second SD4 that I can upgrade to on board control cleaner supports nema 17 motors on all axis ED3 v6. And I have pondered a scratch build for printer #2 now that I have an idea of what I want in a printer and what I do not like. And I can buy a few parts at a time .
I will know what printer # 2 will be when I either order it or build it.
So you need to decide what features are important to you and focus on those or set a price point you are comfortable with and get the best you can under the limit.
I wanted a heated bed an assembled printer and something that does not look like it escaped from a high school robotics lab.
And I am learning that likely the one feature to focus on is a good extruder. as the high end materials become more available you will be out in the cold if you can not reach the higher temps. It is where the rubber hits the road or where the ninjaflex meets the print bed.
Tin
Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura