I'm using the Noreve-Flip-Case for the Mozart, had to bend the sides a little but now my little Julius Amadeus sits tight as hell. very good protection, very, very nice design, can only recommend that case!
If anyone wants my otterbox its for sale, ship anywhere in Europe. I got a thread on market place, Its relativly new hardly used. Anyway check the thread out!
I do not use a case, though I must admit that the Otterbox case looks very nice, I see they are out of stock on the Mobilefun website, but are due soon for a price of £24,95
I use the case mate barely there case - solid and very thin, so doesnt add to the bulk of the device.
I did just replace the back and screen of my Mozart quite easily though, so you can just use it with nothing and replace both if it gets messed up. Plus the gorilla glass should be pretty scratch resistant anyway.