I have used a real deal west-side barbell RH on several occasions. (the strap kind) I have also built my own "Redneck rev hyper" attachment for my EFS 2X2 rack. ( I can add pics later, I'm at work now...) Other than obvious cosmetic differences, comfort levels -ie, mine isn't as padded as Lou's, and weight limits of the 'machine' I can tell little to no difference in the feel of the movement.
If your low back is beat up all he time from squatting and such this will help you. Oh, and BTW I spent $68 on mine. So 1/10 the cost, 98% the benefit is a win-win for me. Mine is similar to this I guess only I get on mine in the front of the rack.
Hope this helps.