Within the parameters as set, I would firmly be in the AR15 camp.
If caliber/weight concerned me much (double duty hunting) I would look at a 6.8 variant and at reasonable ranges I wouldn't feel undergunned running a 300BO with a good quality 110-130gr bullet.
If distances dictate more power I have bolt guns for that and plenty of time to transition to the carbine if ranges shorten.
