Ive had mine on since May, makes the MBP grippy, less slippery (which I like). After spending nearly 3K on my first Mac, ill take the aesthetic hit for not having scratches all over it, plus their warranty is great. Take your time installing, and you will be fine.
Search the internet for discount codes...30-50% off are common!
Be careful when you decide to take it off. When I was pulling the bottom piece of the zagg shield of my MBP and it also removed with it the fcc label. Not a big deal, but it did happen...