Im thinking about buying one of these, but i have questions. First off does anyone have one? if so tell me about it. Also with the predator rail, or i guess any rail that has a sleeve over the upper receiver, how much does it affect sight picture, is it hard to line up the sights? do you need some sort of cheek rest or somthing? I would put an Eotech on it. Is it worth the extra money, the other option i think would be a CMMG midlegnth m4 type of some sort. let me know what you guys think.