my dad was telling me that he's had his phone for 8 days and on average drops at least two calls a day. Now admittedly at&t isn't perfect where we are (but pretty good, i've got 5 bars right now), and he does spend a lot of time on the phone. In his defense he doesn't death grip it either so...
For what it's worth, I can't remember the last time I actually dropped a call with the 3g, in an area where there was actually service in the first place.
I would like to check out the bumpers though, if they're nice it may not be too bad. I ran my 3g case free from 8/2008 until 3/2010 when I got concerned about dropping it a few times

I have to be honest and say that I absolutely hate the feel of the phone (3g) in a case. so much better without.
For what it's worth, this was an interesting track for Apple to take, and I think without traditional media outcry (more than just the salty internet nerds on blogs, who steve jobs reputedly hates)- they wouldn't have bothered, as the original 'you're holding it wrong' messages seem to attest.
I don't know if any of you guys were apple users in the mid nineties, but there were other instances of things that didn't even come close to 'it just works' and users were basically told to go and stuff it where the sun don't shine.
It's also possible that apple's reasoning for actually doing something is that their stock took a $9.9bil hit yesterday.