I have not owned a LifeProof case. I have known beta testers though and they love it. I have only owned the Otterbox, Marware and various cheap cases. Otterbox and Marware are the only two I have personally own and would recommend. Everything else I have seen is just a waste of money.
I go with the Marware
iPhone cases over the Otterbox cases just because they are cheaper and work out just as well for me. However, you might want to pay a bit more to get the full on protection.
I did lose a phone into the ocean once and from what I hear the LifeProof case is the ONLY case that would have saved my phone but it wasn't even out yet. Lucky for me, the iPhone wasn't even out yet.