Does anyone have any information/experience with the shells for your MBP? I had thought about getting one for my MBP but I have read issues of the cases scratching the laptop as well as the plastic clips holding the case snapping off after a month or two. Seeing as how most of these cases are around $40-$50, I just wanted to see if this was a good idea or if I should just say screw it and get a sleeve instead. Thanks.