Returned mine today. After having the phone for a few days, I realized that I could live with my 3GS just fine, better in some ways. I found that I prefer the curved, "sticky" plastic back of the 3GS over the newer "boxy" form of iphone 4. -- just easier and more comfortable to hold IMO. The 3GS is also a bit lighter and less "dense" feeling; the trade off for a larger, more robust battery. And yes, I had reception issues from day 1 that did affect call quality. Incidentally, I tried the scotch tape trick which.. worked. I will surely miss that screen though.
..But what bugs me here is the fact that Apple knew that attenuation was going to be an issue(don't kid yourselves otherwise), yet had the balls to introduce the "bumper" for an absurd premium of$30. $14.99, ok fine but $30 is a goddamn insult to it's customers. *end rant*
Look at BestBuy. All the other iPhone 4 cases are $25-30.
Everyone charges a lot of extra money for peripherals and add-ons. Get over it.