I've got about 19,000 on mine and I think it's just as good as the day I bought it. I garage my bike, which probably helps. I put my 250 pound self on it, which must take a toll. I expect it to last a lot longer.
mines holdin' up well.. i couldn't tell ya how many miles it has on it but it's quite a few. mine should last a while though since i'm a light weight(180-185lbs). they are really durable and amazin' seats.