My husband doesn't use a case, and it doesn't have any reception issues and it has no scratches.
The first day he babied it like crazy. Now it's just a phone so he tosses it around like a maniac. He pretended to drop it the other day, and my heart jumped.
Funny thing is his 3GS, 3G and original iPhone all had cases and all of mine didn't. Now he doesn't use a case because the cases make the phone stick to his pockets. But the iPhone 4 is so pretty I bought a bumper earlier today. I'm debating whether to put it on or not. I may return it and wait for another color.
But it's such a pretty phone I am scared I'll drop it, a horse will run by and step on it and then a street cleaning car will drive by and sweep it away all in the blink of an eye. Not sure why I think a bumper will help my nightmare scenario, but thus is life 😀