The Otterbox 'Impact' - despite it's macho-sounding name - will not make your iPhone indestructible. So, if you're a builder or work in a dusty environment this may not be the one for you. Apart from a clear film screen protector (supplied) the screen is uncovered and the top and bottom ports, speakers, microphone, and camera are permanently open and accessible - even the shiny Apple logo on the back of your phone remains uncovered. (I guess to pander to the "Hey everybody, look, I've got an iPhone" crowd).
That said, I do like this case. Ever since my first iPhone lost an argument with a quarry tile floor, I have had fairly robust cases. Without exception, these have looked klunky and managed to destroy the iPhone's elegance and impede it's usability. The 'Impact' reaches a happy compromise: it's one of the more interesting rubber designs currently available, with a raised, X-shape rear moulding and very grippy sides - you'd have to try hard to let it slip from your fingers. If you did drop it, however, extra thick rubber at the corners should cushion the impact (hey, maybe that's why they...) The Home, Volume and On/Off buttons are covered yet still work perfectly. The ringer on/off slider remains uncovered. The supplied screen protector seems to be very scratch resistant and doesn't affect sensitivity or visibility. The bottom and top ports are accessory compatible. Included in the package are: Case, Screen Protector, Applicator and MicroFibre cloth.
So, not perfect but if you want a good degree of protection without impeding usability this could be the case for you.