Froglube is a great lubricant for some purposes, however, I do not feel that it is a good EP type lube. I would follow mil-spec recommendations in THIS INSTANCE and use a good grease. There are too many good greases, and too many fans of various greases to make it worth debating which one. I simply feel that Froglube's main forte is its ability to remain "wet". The AR's is the perfect weapon for it to be used in, as the only real "high pressure" areas are the bolt-lugs and the cam-pin/bolt-hole area. The bolt is a failure point, anyway, and lube doesn't likely influence that much one way or the other. However, it DOES remove debris from critical tolerance areas, and provide lubrication for the weapon to cycle. An AR will run with vagisil on it as Pat Rogers has proven...but it DOES burn off fast. Froglube doesn't. It also does a pretty good job of corrosion protection, as well. It is not the best wear-preventative out there, though, especially for high-pressure/shock wear prevention.
AR=Froglube (in-line forces, not much use for an EP lube)
Metal pistol-rails=Weaponshield grease or Brian Enos slide glide (EP lube a huge bonus due to the rails pushing against each other like a teeter-totter upon firing).
Benelli M4=TW25B (off-axis forces of steel BCG in an aluminum receiver require an EP type lube, here, IMO).
Just my take.