I move around a lot in the corners (read: hang off the side like a spider monkey), and had worn the seam off where the seat section met the front of the tank. It's the seam under where one's crotch would sit on my bike pictured here:
It was well constructed, but I noted that his later designs eliminated this seam. Not sure if others had issues, but it was that one seam that wore out. Rest of the seat itself was fine, but the heating element under the rider section had quit (possibly due to water intrusion from the worn-through seam.