Hi, a friend insists I buy a glass protector for my new 5s. One of the tempered glass type that can be found on eBay, Amazon, BestyBuy and all the rest. I want to, but are these glass protector invisible enough they want either blur the vision or cause a decrease in brightness. Plus, can they be removed easily? Thanks for the input. I never installed a glass protector on any of my Android phones. R.