If you look at Leadshine's website, they say this about there "Easy Servo"

A Leadshine integrated easy servo motor consists of a high torque stepper motor, a rotary encoder, and an integrated DSP-based digital easy servo drive.
So they are really just a closed loop stepper system.

Look at these:
http://www.aliexpress.com/store/prod...694412844.html

and these:
http://www.aliexpress.com/store/prod...556629526.html