I have an iPhone 4 and I've been able to drop to no bars in the same spot I had 5 bars previously, so in my experience the "depends on how strong the original signal is" argument doesn't stand up. I can stand in the same spot (so the signal strength shouldn't be wildly different) and experience little to no signal loss with a clean dry hand touching the lower left corner, but if my hand is damp from perspiration or the natural build up of oil I experience a drop to zero bars in a matter of seconds. All this makes sense though, since the salty sweat/oil should be more conductive than a clean dry hand. I like the iPhone, but I don't care for the apologists who refuse to admit there is a problem anymore than I care for the company that won't admit there is an issue.