We recently bought a 5th gen, and liked it at first, but then it went down hill. It had a great out-of-the-box experience, plug and play essentially, first 5-10 prints came out fine. The auto-levelling was great and things were looking good. Shortly after that though, the print head starting bumping while printing, essentially seeming to get stuck for a second and then jumping ahead, leaving some irregularities in the print. There were also times when the printer would stall in the middle of the print and freeze, in a non-recoverable state. Finally, the extruder clogged when swapping filament (don't unload filament when changing, instead cut it and use the load command to force the remaining piece through the heated end to prevent clogging). The problem with the last issue was that the smart extruder is really hard to get at to unclog. We ended up returning the unit.