/diy/ - Do It Yourself

The fun part about 3D printing on homemade printers is that there is always something to tweak and improve. I guess it would not be an exaggeration to say that there are only very few printers that are exactly alike because the owners constantly modify them.
In my opinion, this is one very essential part about this hobby.

Of course you could also go the prefabricated route and buy a complete printer (which still is modifiable). In this case, be prepared to pay much more than what you would for parts kits or buying every single part separately.
Still, if you do want a complete printer, and have a lot of money to spend, the best currently available one is the Ultimaker (which you still have to assemble yourself). It costs about 1500$ or so, though. Since it is completely open source, you could also copy the design partially/fully and build your own for less.
In this case, let me elaborate why this is one of the best designs out there (don't misunderstand though, the Mendel90 is still the best low-cost and simplicity oriented design):
The X and Y axes have to move little mass compared to other designs (which is also the reason behind why the Ultimaker is also the fastest printer currently available). All motors are in fixed positions and the bowden extruder design eliminates most of the mass of the printhead. The build platform only moves in Z direction, eliminating wobble in your print (compared to e.g. All Mendel-derived designs with the platform moving in Y direction, which also adds accelerated mass).
The boxy design is also easy to insulate and seal so that you can theoretically keep a constant temperature around the print (resulting in higher quality output) and extract and filter fumes (good for printing ABS which sometimes releases nasty fumes).