my thoughts on the OBR and its variants are that they are way over priced for what it is, for what they are going for now, you are getting into the HK and Knights pricing area, hell you could get an MWS with optics for about the same as a stripped predatarOBR. all three systems bring a pretty significant level of innovation to the table.( enhanced bolts, pistons,qd barrels, ect...)
all three choices are much better rifles based on actually test data in addition to actual employment in combat.
if your main concern is accuracy, i suggest taking a look at a GA precision, as they use better barrels and can cut the chamber for what ever round you like, they have over 30 different chamber reamers for 308, larue has 1. additionally if your interested in long range ballistics you can get a ga precision or LMT MWS in 6.5 or .260 that will that smoke a 308 long range.
the OBR is nice and all, but it really doesnt have anything on any other 308 AR with match barrel, and Gieselle trigger.