The ATACR would be a incredibly well matched optic for that rifle and those distances. I really think you will find yourself using and enjoying the higher magnification. Just because it's there, doesn't mean it has to be utilized, but I really think you will get a lot of use out of it.
The US optic vs nigtforce debate will have its fans on each side of the fence. They are both outstanding companies with amazing products, but I have always landed on the nightforce side of the fence. If I wasn't going to spend my money on a NF I'd probably look at the Leupold 6s. I don't see that ever happening either though. There has been some talk of a 1-6 or a 1-8 NF soon, but again, those would be on my SBRs that see a lot of close up targets.
The TOBR will love the ATACR, and so will you.