Yes TP, I have the CNC Router Parts R&P system, which has a 3:1 belt reduction. I'm also using 495oz NEMA 23 motors which should be sufficient.
How did you determine this was sufficient? How much weight are you trying to move? How smoothly does it move. What kind of drives, and what power supply voltage?
Most people use the 381oz motors with a G540, which will usually outperform the 495's by a good margin, due to their lower inductance.
Imo, Nema 23 motors are too small for a 5x10 machine, and I also don't think the 3:1 reduction is enough for a heavier machine.
For the 4x6 router I'm building, I've calculated that I'll need 570oz motors and 4:1 reduction to get the performance I want. (150-200 accel up to 500ipm)