If you are looking for a tac driver that will not fail then get the MR223, Greentips is selling one, get an enhanced trigger guard and KAC ambi selector switch from OST for her and your good to go. I would run a trijicon Acog of some type with the docter sight on top and call it a day..You will need Emags though for the PMAGS will not fit in the HK magazine housing. Although I have herd the new PMAGS versions have been changed now...rumor can not confirm. Questar and Blaxsun has the EMAGS.
The MR223 is more of a "Battle Carbine" if there was ever a term in the sense it is a little heavier than your average AR but you get some benefits, and really the weight is nothing for the added capability. The rifle is solid and built for durability accuracy and at an extremely high quality level that goes beyond most AR I have seen on the market by a long shot. If you want a gun that does it all and does it at the highest level then look no further...I wouldn't sell mine for anything else.