SGP Neo Hybrid, the 4 just does not instill confidence that it will survive the typical life of a cell phone. Also, at my new job the signal inside is weak and I can induce the death grip from 3-4 to 1 bar.
For you bumper users, I'd check to see how your antenna looks after a little bit. A good majority are scratched up.
How often did you take it on and off and how long did have you had it? I had a launch day i4 and got my free bumper (never had the issue it was supposed to fix) and man it tore it up. However when I replaced my iPhone, the antenna surface was different. I roll nekkid now since I never had the issue and am fearful of scratching it up again. Plus at 30 bucks, it's waaaaaaaaaay overpriced and just looks damn good nekkid.