Had the OBR in 7.62. Went head to head against h&k, scar and POF. Accuracy went to the H&K. Reliability went to the scar mainly because of their attention to making a solid metal magazine. POF and Larue were pretty close to each other. Larue has a great fit and finish. Customer support is top notch. They make some fine firearms. The best grouping we could get from 4 different ammo manufacturers was .75 inches on the Larue. To rule out some possible changing variables we used the same scope on each rifle, same ammo from same batch runs and all on the same day. We used two different shooters for each ten shot run.
H&K is an expensive option and you can not get a 20" upper, FN less expensive by almost half and likewise no chance to get a 20" upper. Larue fell right between these two for accuracy and reliability. Coincidentally it is also a several hundred dollars less than the H&K.
Magazines for the FN and H&K are proprietary and cost around $40 (fn) and $80 (HK). Larue and the POF take Pmags at about $20 each.
I sold the Larue and the POF. The Larue did not produce the accuracy I wanted and it was a 20" upper. The POF did a little better, but they were developing and had just released the gen 4 of their line. Since mine was the gen 3 I let it go as well.
They are all good rifles. The cost and availability of accessories will play a role in your decision to be sure. If I could get a 20" upper for the H$K it would be my preferred rifle even with the outrageous magazine expense. Ahh but if wishes were horses, dreamers would ride. Hope that helped some.