I've just finished my machine.. I've got the Hobby CNC 4Axis Pro kit with the 305 oz motors.. I'm quite happy with that..
I can already tell though, my first upgrade for this machine is going to be doing away with the 1/4 20 all thread and get some faster screws. As far as spindle goes.. look at the Bosch Colt palm router. I'm quite pleased with it..