I do. I have a Ti rod that runs from my right hip to just above my knee as a result of a horrible femur fracture a while back. The hip abductor and the adductor machines are regular part of my strength training based on the recommendation of my then physical therapist. It had to do with the fact that I had lost some muscle mass on my right femur while recuperating from my the femur break.

I can't really tell you what the benefits is/are, but I really enjoy doing them as part of my total fitness plan. One thing I can tell you though, is that my bum leg fatigues less quicker than the good leg. I would like to believe it is b/cos I take my leg exercises (leg press, quad lift, standing hamstring curls, calf presses and calf lifts) very seriously. I am a kinda serious hiker too, and that probaly helps too.