I've had all three, and the casemate POP is by far the best.
The seidio, is silicone on the inside with a hard plastic skeleton that snaps on. Kinda like the POP case, but 2 pieces. Nice case, slightly more bulky than the POP, but my biggest complaint is that the edges around the screen aren't bevelled so you're constantly bumping it while typing, scrolling etc.
Otterbox is tough. I could throw my phone through the wall with that thing on it. Bevelled edges so you don't bump it all the time. But it has a screen protector built in that traps dust. Very annoying, and its just too big.
POP case I have a black one and a white one I like it so much. Snaps on very snugly, great protection, you wont constantly be bumping it while using your phone. The only downside and its not really a downside as its only temporary, is that the power button is a little tough to push for a couple weeks until its broken in a bit.
All this being said, Ive been rocking the phone naked with a screen protector for the past month or so, and can't see myself going back unless I know ill be doing something where I need the extra protection, in which case, POP it is. Naked is where its at day to day. I pay extra to have insurance for a reason after all..
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