Hybrid Steppers (With Encoder and feedback controller) Anybody using?

I know they're new to the market, But I'm working on a heavy duty mill design (somewhere between Gantry mill and Way guided conventional Mini mill), and Servos or feedback will be required. The parts I'll be making won't be disposable, so missed steps aren't allowed, and the Steppers with an encoder and feedback controller are available from the Chinese market (Leadshine et Al) from about $200/axis and up. Parkers and good quality Industrial are more like $1000/axis minimum.

Does anybody...

Hybrid Steppers (With Encoder and feedback controller) Anybody using?