If you're going for increased precision, don't cheap out on the frame. 80/20 (assembled with a machinist's square) and linear bearings are the way to go (from the options you've listed).
Type: Posts; User: Davo
If you're going for increased precision, don't cheap out on the frame. 80/20 (assembled with a machinist's square) and linear bearings are the way to go (from the options you've listed).