Servo motor question

Hi Group,

I have a BP Series 1 that had a Boss 5 control driving the big old
finned stepper motors. I switched out the steppers with some extra
servomotors and share the drive system that I use for my plasma.
Here's my question for you motor experts, would it be a better match
to use the steppers as opposed to the servos? The reason I ask is
the feed speeds I'm running I.E. 20IPM with a .200 ballscrew and a
1/1 on motor have the servo running at 100RPM. I'm I hurting the
motors and will they last at this speed? They seem to work fine.
Reading the board started me thinking about this, as I read steppers
have low speed torque and servos like higher RPMs. If would seem
steppers would be more appropriate for this speed range. However the
Centroid conversion uses a 1/1 ratio with servos! Maybe they work
with brute power. The servos I using have a Kt 37.5 Oz –in/A,
drivers are G340. Any suggestion or info would be appreciated.
Thanks Harry