Have left a couple of months 'til reviewing this as I tried other cases before (eg the Exspect flip case for iPhone4, as the one I'd had for my old 3G had been very good) which started off seeming great, but didn't hold up well under continued use :(
So far this seems brilliant! Really like that it has a popper closure rather than velcro (tacky and liable to come away) or magnetic (don't like the idea of magnets close to tech gadgets). I always prefer to have a flip over cover as well to protect the screen. The bonded leather really makes it though - it actually seems to be genuine and is wearing in beautifully, compared to a lot of the cases that claim to be leather but turn out to be mostly koskin or similar.
Main case clips around the phone fairly securely; doesn't feel like it's going to fall out, but not too much of a job to remove the phone again. Cutouts all present and correct, with plenty of space round the camera & flash.
Definitely recommended if you prefer flip cover cases.