I wouldn't recommend the Speck Candyshell to anyone. It use to be my favorite case for the 3G, but for my iPhone 4, it's been nothing but a disappointment. I had this for two months and I was just disgusted in what happened to the case with normal everyday usage (Notice the peeling of the silicone)... I even tried to get a replacement and they refused to send me one.
My friend purchased one of the 'newer' models with the bigger camera cut out and he had the exact same problem I did. I definitely wouldn't recommend spending $35 on a case for this to happen just after a month or two of using it.
I'm seconding this in a HUGE way.
Bought a black Speck CandyShell for my 4S in mid January. 3 days after purchase, the rubber parts of it were peeling and 'smearing' on the Speck logo in particular. So I took it to the Apple store and they exchanged it, waived the fee.
6 weeks later, I'm on my second one now, and I've got actual chunks of the rubber crumbling away. Its obviously where my fingertips touch those parts during normal handheld use. Right by the volume buttons, right above the lower speaker (where your pinkie finger goes) and then on the opposite side where your thumb would rest naturally. The back is covered with scratches and while I expect that (that is the purpose after all of a case) it is very soft and scratches very easily. It does seem to protect the 4S very well but it just looks like crap.
I called Speck, was told that the peeling must be due to my "misuse" of the product. If holding your damn phone constitutes "misuse" then Speck's product is unusable to me.
No more Speck CandyShell for me. I just bought the cheap Magpull Fieldcase and it looks, fits and behaves like a cover should at 1/4 the price of the CandyShell.