I just sold my iPhone 4 on a local auction site. Now I got back all my costs, not just the phone with Apple's refund offer.

It's a superior device but with the most interfere prone antenna. I'll buy a temporary Nokia C5 or something similar cheap and be back with the iPhone when Apple gets a decent antenna. (I already sold my old 3GS, too)

The problem effects every 3G network out there, not just AT&T. But it's not the same for everyone, depends how you hold the phone usually, left or right hand, how your body reacts as an antenna, size of your hand, etc. I get full bars (4.0.1) on 3G and data transfer rates over 5 Mbit/s here at home if I don't touch the phone -- if I hold it normally for web browsing, like I hold the 3GS, the phone can drop from 3G down to GSM.

The legal environment in the US probably prevents Apple from to acknowledge there's a problem.