I have not shot and M14 or an HK-91, but I have shot the FAL. From what I've read, the FAL can be heinous if you get a lemon, but the one I shot was AWESOME. I expected to pick it up and have marginal accuracy with open sights. In reality I was able to put 3 shots into a coke can at 50 yards in less than three seconds. IMO that's impressive for a .308 with open sights. Kick was VERY manageable, and the weapon cycled flawlessly through several 20 round mags. I'd be very interested to see what I could do with a scope at 500-800 yards. The first three words out of my mouth after firing were "I...WANT...ONE!" From a tactical standpoint, it seems the FAL and the M14 would both be faster to load, since the charging handle on the HK is so far forward (HK charging would be ABYSMALLY slow for a lefty), and I supposed the M14 would be on a level with the FAL in this respect. Maybe not a huge issue for right handed people, but as a lefty I would steer clear of the HK. I've only ever heard good things about the M14 as well, but I think I would choose the FAL. I hope someone finds this useful.