RE: big Gecko question

Morning all , The 4 axis machine center that I am looking at has dc
servo motors with Tachometers on the back of them. The Fanuc control
is dead and obsolete and I would like to replace it with something .
Now would Gecko Servo drives be good enough to drive such a monster?
if the motors are within the 80 volts and 20 amp range then what is
the limit in machine size that a Gecko servo drive can handle or is
that immaterial? Looking forward to your replies
Mark