It depends on your purpose for the rifle and budget. If just plinking around at 25-100 yards, their MRO would suit you just fine. $400-$450I think I'm going to put a Geissele trigger in it. Then save the money and just throw a trijicon on it. Any recommendations on what trijicon to use?
If you want to shoot at more distance, and have a better view of things, you could try their Accupoint 1-4 or 1-6 $750-$1200
Their are other great options if the above two do not fit your needs, not just within the Trijicon brand either. I personally dislike ACOGs. You are stuck with either 1.5,3,4,etc....fixed power and the eye relief is not very good. The newer 1-4,1-6,1-8 scope hitting the market have come a long ways in the past years and are a much better and more flexible option IMHO.