Never tried a 1 piece seal yet, but I know the 5+ failures I've had of OEM seals (and atkins.....) were breakages that occured at the very tip of the long portion of the seal, where it meets the corner piece. Given that alone, I'd say a 1 piece seal might take 2-3 more pings vs. a 2 pc. Of course, when it does fail, its probably going to take a lot more stuff with it too
Also, I know the dynamic compression of 1piece seals is not as high as 2piece given the sealing surface of the 2 piece can move around a little more and "fit" the housing/irons better.