Having just bought a 13" Macbook Pro i5 (non-retina) I need some sort of protection for it. It'll be placed in a backpack when traveling, so I only need something to protect mainly against scratches and minor bumps. Neoprene sleeves are compact and would protect against bumps, but all the ones I've seen come with zippers which kind of defeat the purpose of protecting against scratches. Then there are these "shells" of hard plastic or rubber. This seems like an even better idea because they'd protect the computer against scratches at all times -even while using it. I like the idea of a "grippy" rubbery outer protection, but I'm not sure what to get. Will the cheapo eBay "rubber shells" suffice or should I look into something else?