If the Survivor were waterproof...
OR, the Lifeproof had better shock protection, either one would be the almost perfect case. And, I'd lean towards the Lifeproof, if all things were equal between the two.
I had a white Lifeproof case, and didn't have any of the reported issues with it. The light sensor worked fine, the touchscreen worked with normal pressure, and the sound was clear. It also does not feel cheap [YMMV], but very solid, IMO. Further, it adds very little to the overall size of the phone. The main reason I returned it, was that it didn't really offer a lot of shock protection. Even from the videos on their website, Lifeproof doesn't advise letting too much happen to your case, in the way of getting dropped, or otherwise knocked about, lest its water resistant qualities be affected. If it could withstand the kind of treatment that the Survivor can take, I would have been glad to keep it.
The Survivor, on the other hand, was able to protect an iPhone dropped 12 stories from a bridge, without any signs of damage whatsoever.
Survivor dropped off a 12 story bridge The only thing it lacks, is that it doesn't offer the level of water resistance that the lifeproof does. Also, I have seen it in person, and it is really not that large a case, for what it provides. In fact, it is shorter than the lifeproof, and not much wider. I was able to easily carry it in my front pocket, without issue.
At the immediate moment, I'm using a Griffin Protector case, in yellow.
For the record, my iPhone 3GS was carried in a Speck ArmorSkin silicone case, hands down the best case I ever owned for it. It's unfortunate they don't have any equivalent case now...
My $.02,
Frank