I have the speck case. It adds some bulk but it's not too bad, definately worth the protection it provides. I can pretty much toss it into my bag and set it down on the table less-than-gently. I also struck the case a few times with absolutely no damage to the exterior (cleaned it last week). The clear one (all of them ,really) will also allow you to do a bit of non permanent customization; i've done so with designs printed on transparencies placed inbetween the case and the MBP. It's not so much as to prevent scratches (though my machine has absolutely zero scratches on the body) but to prevent impact damage, which it has done flawlessly.