I wonder how much of this is a real problem in normal usage?
Did you try YOUR "defective" iPhone 4 in the same place in the Apple store? You know all Apple stores have a mini cell site in the back (affectionately referred to as the cancer boxes) so the signal is going to be super strong. Maybe you don't see the problem for this reason.I had the signal problem with my first i4, swapped it out with a 2nd one, same thing. I returned it, will wait for the iPhone 4.5
I did notice that while I could easily reproduce the problem in the Apple Store, their display models didn't have the problem. So... it's not a problem with all of the iPhone 4's, but it definitely is for some. Just imagine, all the ones that are having the problem and being returned will eventually wind up as refurbs used as replacements -- ohoh...
It's funny, the day I got my iPhone 4 (Launch Day @ Apple) my first 2 phone calls were dropped during the conversation. I haven't gotten a dropped call since.
The strange thing I'm noticing though is when I'm on safari, I would sometimes experience a 4-5 second period where the app just freezes. Could that be due to this reception issue? I've checked off a couple possible factors like multiple apps open, or no 3G/Wi-fi signal, but to no avail...