I just finished printing the plastic parts for my new 3d printer, a Kossel Mini, to be built from a very nice kit sold at think3dprint3d.com. Some issues I ran into so far:
-the extruder motor spacer was missing (quickly added by think3dprint3d)
-the legs on the LCD panel were a bit long and would only fit when heightening the printer considerably (quickly fixed by think3dprint3d, awesome!)
-the z-probe pin hole is modeled way too big. while the pin is only 1.5mm thick, the hole is 2.6mm, so I had to print the z-probe holder twice.
-the hole made in the effector is only 4mm deep, whereas the hotend I received requires a 4.8mm hole.
-the anti-chatter parts are a bit ugly, so I replaced them with pull springs, attached with zipties.
-I couldn't find the new extruder mounter, so took it from elmuchacho's thingiverse account
-homing speed by default is set a bit high in the provided marlin firmware. it at least made me turn off my printer very quickly while homing for the first time.
Other than these issues (which you mostly won't run into with the provided plastic parts), I can highly recommend this kit to anyone who would like to build a reprap-style delta printer (with out-of-the-box heated bed). For me the biggest thing which is still missing is dual extrusion, to enable dissolvable support structures.
I hope to report after calibration on the resulting precision of printed parts. If it's really good (z-precision wise), I intend to also play with cold acetone vapor to see what happens to precisely printed mechanical parts.