Have an opportunity to trade my 3rd gen. Ipad 32gb wifi only for a 4th gen. 16gb wifi+4g ipad. I would have to give 75 dollars boot, which seems fair considering what each ipad is going for used. The 4th gen ipad is flawless, except for a scratch on the screen that is about an inch and a half long. Does this sound like a good trade? I don't store a lot on my ipad, so losing storage isn't a big deal. My only concern is that scratch. I always keep my stuff in mint condition, and that scratch would really big me. Do you think an invisible shield would hide the scratch? It's not real deep, but it's not really light either. You can feel it when you run your fingernail over it. Thanks for any input.