I have a Lifeproof for my iP4 and I love it! Don't think I will ever go back to Otterbox. As a matter of fact, I am holding off on getting the iP5 until the Lifeproof is released, which may be sometime next month (I hope). I used to only use the Otterbox Defender, but I was able to pick up a Lifeproof for my iP4 for 25% off at AT&T making it about the same price as an Otterbox Defender. In my opinion, the screen protector on the Lifeproof makes the screen much clearer than the Defender and I liked the slimmer form of the Lifeproof as compared to the Defender. I also didn't like the fact that the rubber on the Defender was a lint/dirt magnet and tended to stretch out over time. I have heard that the new Defenders for the iP5 use a different rubber that is much improved in this area, so maybe the new ones won't have that issue.
With all that being said, I have always been OCD when it comes to a naked phone. It's always scared the crap out of me, mainly because I'm clumsy and susceptible to dropping my phone. The thoughts of it hitting the ground unprotected makes me cringe. So I refuse to even walk out of the store without my new iP5 being in a case. Sure a naked iPhone is beautiful, but I'm a realist. I can replace a bummed up case much easier than a broken screen. If I were you, I'd get the Defender for now and upgrade to the Lifeproof once it comes out. Just my two cents . . . 😉