A couple of years ago, I got started with my 3D printer, an I3 clone.
It wasn't a great kit to start with, and I have never been entirely happy with its overall accuracy. I always felt that I was making compromises with many of the things that I made with it. I made several improvements, and it got better, but it's still not as good as I want. I have never been able to make pieces that fit tightly together without needing to adjust for a difference between expected and actual real dimensions. (Say making a slot and tab assembly part.) I'm interested in the accuracy that this allows.
I had thought that perhaps the T8 lead screws would pose a speed problem. With a 4 start 2mm pitch, and a 1.8 degree stepper motor, at 1/16 microstepping, I get 400 steps/mm, which is about double that of a typical GT2 belt setup. It seems to be that changing to 1/8 microstepping should result in similar speeds, even though the motor RPM will double.
I am planning to rebuild by printer similar to this myself, so I'm encouraged by the success of this one.
Prusa i3 / Arduino Mega 2560 / RAMPS 1.4
Kit from a2aprinter
Beltless redesign in progress to move to T8 lead screw drive
Kit from Amazon
Some teething pains, but a reasonably good printer, just missing a heated bed.