I agree with millsy: slim to none. I'd bet that the design will change for the next iPhone iteration, though. I
do think it's an issue, and not a small one, for a company that prides itself on technology that "just works."
The iPhone 4 isn't the perfect RF device. It has lots of strengths. Nothing, and no one, is actually perfect.
True, but for the $700 unsubsidized cost of the phone, it should at least be able to connect to its (only) network flawlessly. After all, without a network the device isn't fully useable.
As for myself, I'm getting the phone because I always get a case anyway, so this problem won't affect me. Even with its flaw it will be a big improvement over my 2nd generation iPhone. But it's such a simple problem to understand, I'm shocked that the iPhone made it into production with it. There must have been enormous pressure to finalize the device. Jobs at least could have said something like "We know there's a problem and we're working on it." But to completely blow it off isn't good PR. For many people, it
is an issue. And this is supposed to be the Rolls Royce of phones.
I'm wondering why they didn't just keep the antennae inside the phone. Now that the entire body is glass, signal blockage wouldn't be as serious an issue. Even if there were a thin glass coating around the stainless steel, so the band was visible under the surface, that would have completely eliminated the problem.
iPhone 4 has so many improvements, it sad to see it take such a leap backwards over one (very important) issue.
(And P.S. -- $30 for the bumpers is extortion. Apple should price them at $5 and include a free black one with the phone.)