Gecko g320 or g340 servo drives, anyone here use them?

Does anyone have any experience with these drives?

I'm trying to figure empirically and theoretically if
servos
will work in my application and I don't have any
experience
with servos other than owning a machine w/working servos.
I was wondering if someone has applied servos with Gecko
G320 or G340 drives, in what application and what were
the
results? Speeds obtained, max. and while milling. What
motors were used? What was the pitch of the ball screws?
I'm trying to drive the X+Y axes on a 3 HP mill w/5 tpi
lead ball screws w/no backlash, ball bearing ways, it was
originally driven by 400 in. oz. unipolar steppers at 10
in./min.

Thank you Bob