So many choices - Best way to make Sherline CNC

I'm know that this has been asked over and over again but cannot find
one with this twist. There are basically (as I understand it) 2
options to convert a Sherline Mill to CNC. 1 would be to use stepper
motors, and another (?) to use servo motors. My question is which is
better and more accurate? In my browsing I noticed that the servo
kits (e.g., G320) and motors use feedback, this verifies position,
move, etc. I've seen/heard of stepper motors that have encoders on
them but haven't seen a driver that supports feedback directly
(unless I'm missing something). So my question holds; what is the
best for the $ if you want accuracy (is feedback really
required/best)? Oh, consider that I've noticed that Camtronics is
out of 5A driver (if that would have been the way to go).

Thanks,
Ken