Advice on buying servos.

[Gary]

Thanks. I notice that you have both DC brushless and AC servos on your website - what are the advantages and disadvantages?

One take DC and the other takes AC, so the AC servo driver has a power supply built in that is rated to the nominal and peak rated current of the driver.
Also Just because it's a DC servo does not mean its brushed, a DC servo can be brushed or brushless.