The LAR-8 that I'm looking for would cost me about $1800 with upgraded quad rail. Would you pay the extra $1000 for the POF .308? In other words, is it actually worth the decent sized difference in price? (I realize it's impingement versus piston) I have also been eyeing the predator version of the LaRue, but either that or the POF are going to take me a long time to save for.
It's worth it if you need what they offer. The PredatOBR isn't really worth it because it's basically a heavy barreled predatar with a better gas system, it lacks the thicker upper receiver making it loose one of the primary advantage of the OBR. The P308 has a thicker upper and a heat sink barrel nut allowing it to be more accurate. This thicker receivers flex less making it more accurate. The PredatOBR has a standard thickness upper so it is less accurate. Both the P308 and the OBR's handguard doesn't mount to the barrel nut. I have noticed that piston guns (when properly designed) can be more accurate than DI guns due to less heat being transfered to the chamber area, the hottest part of the barrel. The P308 and OBR will have less vertical stringing than most.
The P308 and OBR are designed for accurately putting lots of lead downrange at long range, the LAR-8 will put lead accurately downrange, but won't have that last bit of accuracy that the P308 and OBR squeeze out. Unless you're doing something that you need to shoot 1/3 MOA for the LAR-8 will serve you well. The LAR-8 I shot would shoot sub MOA about all the time. The LAR-8 is perfect for out to 1000 yards. I feel that the PredatOBR is in the same legue as the LAR-8.
The P308 is easier to clean, needs cleaning less often, and doesn't NEED to be lubed, but it should be because of the NP3. It functions very well in sand, water, and mud.
I wouldn't get a P308 or OBR if you don't plan on shooting at very long ranges often. I wouldn't get a P308 if you don't need the accuracy AND reliability it has; you can get other piston .308's for less. I wouldn't get a PredatOBR unless I wanted to overpay.
If you don't plan on swapping uppers, you are happy with Rock River's selection of handguards, and you don't need anything more than sub MOA performance get the LAR-8.