LMT...
But i'd still get a GAP-10 over either of them..
I was in a class with 2 OBR's and an LMT.. We were shooting MOA sized targets out to 400.. Long story short the OBR guys struggled to hit targets all day. Both of them ended up switching out to their bolt guns and ended up being two of the better shooters in the class with their bolts.. They just couldn't hit the targets with their OBR's. Take it for what it's worth.
Also, the Larue fanboys are heavy here on ar15.com.. If you want an honest assessment ask at a few different sites..
I like the OBR, think it's reliable and the customer service speaks for itself... The accuracy just isn't there. I also think they are over priced, both the GAP-10 and the LMT are cheaper, and there is nothing to justify the additional expense of the OBR..