The bumper is definitely bulkier than the play proof. It's easier to hold them the play but the buttons aren't as good. IMO the play proof of the overall better case.
Yeah I bought both last weekend and found the bumper much bigger as the photo below shows. I also found the buttons harder to press on the play proof but I took the case off and presses the buttons hard, holding them down several times and it made them much easier to press. They are about the same now as the Apple leather cases I have.
I would also say that the play proof is the better case, if only they did some better colours.
