I have one as it was recommended. My boy gets girth galls very easily as he has very little hollow behind his elbow and the skin rumples up easily and rubs. Unfortunately, the Stubben girth made it worse!
But I think he's the exception to the rule, as everyone else raves about them. I bought a £3 fake sheepskin cover instead and problem solved, bloomin' pikey pony...
What size/colour are you looking for? I have one with box for use on non-pikey types, lol