I have a CT129N, go for the CX600! When I got the CT129N, it was the only & biggest 'bench-top' column style mill\drill available, 3/4HP motor, MT3 Spindle. The CX600 has 1HP motor & R8 Spindle.
Also, don't bother with the 'stock' stand, although sturdy, it's too short and 'nil' for storage. I...