Thanks for the replies. Do you just use yours for recovery then Paul?
I think they're most beneficial for training for 60m euro endurance plods, I'd say next to useless for bouldering. They're good for recovery between sessions, but not compared to a decent meal and a night's sleep.
Has anybody who uses one regularly managed to get fingertip contraction, particularly in the index finger? Where did you put the pads? (post a pic).