Hi, My sister is getting an iPhone 4S for Christmas this year. I was in the Apple Store today and noticed they're selling the little black bumpers on the side. What type of protection does this offer versus a case? Will bumpers only protect against a fall on the sides/corners? She's 17, so I believe she needs at least some type of bumper or case at this point. If you know of any links to real-world tests with bumpers (drops from 3 ft, 5 ft, etc.) I would appreciate them. Googling just gave me a bunch of case reviews. Thanks!