Although waterproof, not a good screen protecting case.
I'm guessing you're looking into something thats pretty protective since you're looking at lifeproof cases and looking into spending that kinda dough?
Lifeproof is great in the hands and a lot thinner, as well as water proof. Now, as far as screen protection with life proof. Not so much. There isn't really ANY protection as far as dropping unless its on a corner. I've never had any issues with the touch sensitivity that you're talking about. I did purchase this case in January though and not sure if thats something that was changed. If you're looking for great protection for the phone in general as well as FANTASTIC hassle free customer service I'd go with the otterbox defender case. I use the defender for work since I'm all over the place and up and down quite a bit. I need something that was going to protect against dropping which is what I seem to do most. The downside to that is bulkiness.
Good luck!