We've seen many examples of iPhone 4 reception problems when people hold their devices a certain way, but we're wondering: What about during normal use? Have you experienced reception problems when you're not trying to replicate the so-called death grip?
When you're just holding your iPhone however it's comfortable during calls, browsing, emailing, gaming, or miscellaneous data usage, are you noticing that your reception goes? The problem is, it's hard to tell with bars. A good way to check on this empirically is to run a speed test several times: Once with your device on a table—away from your body—and once while held in your hand however you normally hold it. And once with the death grip. Give it a try and let us know what happens. Is everything fine or is there a big difference?
For almost all of us on staff with iPhone 4s, there is a marked difference between holding it in a pinch, where you don't touch the antennas, and where you connect the two pieces of antenna on the lower left with your hand. Jason's speed test went from 2200kbps/1200kbps when not touching the antennas, to 440kbps/630kbps with touching the antennas. However, his bars only went from 5 down to 4, with the death grip. Basically no major difference in the "display" of how good the reception was, but a major one in how usable it is. Mine went from 1600kbps/1200kbps to 600kbps/460kbps. But my bars didn't change at all.
So, make sure to try the Speed Test app to actually put some numbers to the process. Don't just rely on the bars.