(I am English, apologies for writing this review in English!)
I bought the clear version of this case for a white iPhone 4S. I wanted a case that was clear and that was at least slightly soft in order to give some protection if the phone was dropped, and also to give some grip when holding it. On these points the case is ideal, the material has previously been described as like an escalator handrail and I think this is a good description. It gives enough grip, without being so sticky that it is difficult to remove from a pocket. The fitment is also perfect, and when the case is in place it feels very solid and not prone to being easily pulled off. One thing I particularly like is the way the case covers the plastic edges of the LCD screen, which is something of a weak point on the iPhone 4 design, as these are easily cracked. Hard cases can also crack these edges (even Apple's own 'Bumper' case). When placing the phone face-down on a table the case will stop the screen from touching the surface.
The buttons and connectors are all easily accessed. I use Sennheiser CX-300II headphones and have no problems attaching them with the case in place. The iPhone USB connector can also be used with no issue. The lock button becomes a little stiff to operate due to it being covered completely by the rubber, but works ok. The cut-out for volume and mute are nicely proportioned.
The only slight flaw is, as has previously been mentioned, that the screen protectors tend to lift at the edges on both front and back, due to the tight fit of the case. This is because the protectors cover 100% of the glass area and are squeezed by the edges of the tight case. Were they to cover a slightly smaller area it would perhaps be better, but for me this isn't a major problem as I'm more concerned about protecting the phone from drops, without spoiling the look of the phone, which I think this case does really well.
I would recommend.