Most:
* The hull is neither too thin nor too thick hair cell
* 1/2 1/2 rigid and flexible at the right places: perfect.
* Dead weight: super light.
* Mounting on the phone without the slightest effort, but not as easily disassembled and that's fine.
* The holes and lights for sockets and buttons are the right size and the right place.
* Protects the corners well: thick enough (it will not drop 2m either!)
* The allowance before protects the screen when you put the phone, "face against the ground": it tolerates few millimeters of play.
* Quoted its striated and allow a perfect fit / grip (slip and not messy unlike the "grip" that one sees everywhere!)
* The prize: frankly cheap for this level of quality. Well, I do not say it too loud, otherwise "they" will increase ;-)
* The looks? I find it nice (better in real life than in pictures) and sober. it passes almost unnoticed (if you wanted to get noticed, it missed !!! For me it's perfect.)
The least?
* Usual I "sharp tongue", but then, honestly, I really do not see anything bad ...
Not tested screen protection: my 3GS about 4 years so this is not really a concern for me ...
I recommend buying.