When I got my new iPhone 4, I was advised that it was a lot more fragile than my old one because the back was glass as well as the front. Three different members of staff in the phone shop gave me dire warnings and tried to sell me an insurance policy. I thought it would be better just to get a case. This one was well-reviewed on iLounge. Unfortunately I have been very disappointed about the product and will soon be giving up on it, once I have prised my phone out of it.
The case does seem to offer very sturdy protection from accidental damage. However, that is outweighed for me by the various drawbacks. My phone now feels cumbersome and no longer fits comfortably in my hand. The rubberised case finish is not at all tactile, in fact rather nasty-feeling: I was hoping it would be more like the back of a Kindle. The edges at the back are hard and dig into your hand. The edges at the front are already worn and crumbly after only two or three weeks of use. Dust collects on the screen especially near the edges. On the other hand, the unappealing look of the case does perhaps render my phone less ostentatious in public.
I will be looking for something nicer and more comfortable.