CNC power supply question

Hello,

I'm trying to get the 'big picture' on designing my own servo
based cnc control using a Gecko based system. I'm currently trying
to tackle the power supply issue; Why some kinds are better than
others and how to determine PS size from the motor specs in general.

I've read here and elsewhere that the varying loads associated
with CNC motor control is a problem for commonly available
regulated/switched power supplies.

What makes a 'homemade', unregulated(?), PS (Jerry's PS, or Doug
Fortunes 1kw/1.5kw monsters) better at handling varying loads than
the 'comercial/professional' grade regulated PS you see on Ebay or
other retailers?