I was seriously considering the Candyshell at first, but since I couldn't find one in stores, I settled for the Silicrylic and am quite happy with it. From what I've seen, the Candyshell looks like it would have been too thick for me. The Silicrylic doesn't make the phone that much bigger (not nearly as much as the Candyshell looks like it does) and feels pretty solid.
When I first got it as an emergency case, I wasn't too thrilled with it because of the soft silicone that collects lint and feels like it would stretch and sag pretty easily. And it didn't look as cool as the Switcheasy RebelSerpent I had for my 3G. So I was prepared to return it as soon as something better appeared. But it definitely grew on me and now I love it. The hard acrylic outer shell isn't glossy or shiny, so it doesn't scratch like a black Candyshell would. Mine looks just as new as when I got it. And the inner silicone case looks like it would protect it moderately well even if it didn't have the harder outer shell over it. It's definitely thinner than a stand-alone silicone case, but it works pretty well with the harder shell. And there are no problems pulling it out of your pocket like other silicone-only cases because the hard acrylic covers most of the silicone.
As for the camera, it doesn't interfere at all with my black case. Mine came with an extra yellow silicone case, but I haven't used it yet, so I don't know how that affects the camera.
But overall, I would definitely recommend it.