I've seen Breakfree CLP do enough amazing things to absolutely filthy, sandy, gritty M16s and SAWs that I am convinced there is few better choices on the market. It and lately a little specific application of Tetra Gun Grease, which I originally started using with my M1A but now use in limited quantities elsewhere (bolt lugs on semi-autos like the M1A and the AK, as well as bolt actions, and occasionally on frame or receiver rails of rifles, shotguns, and automatic handguns) is about all I use any more.
But when pulling back the bolt of your M16 feels and sounds like the bolt is wrapped in sandpaper, and the application of a couple drops of anything gets it running almost like new again, that something is pretty awesome and can take care of pretty much anything else you care to use it for. That makes CLP pretty awesome, and I almost what to try it on my nachos now.
RemOil never impressed me. It always seemed to evaporate, along with its protective properties, far too fast for my liking. And the only time I've ever used WD-40 on a firearm is on the extremely rare occasion that I have a firearm get wet without having access to even a makeshift cleaning kit in my pack. Usually such a kit is present when I hunting, for example, but not always in some special circumstances. Then, if I can find a can of Whiskey Delta Forty, such as crammed under the back seat of the pickup truck under half a dozen empty Monster cans and Snicker bar wrappers next to the tire iron or by the paper towels in the cubby of the boat buried by life jackets, I'll spray the gun down in WD-40 as a rust preventive measure as it is stored, relatively short term, until I can gain access to a proper gun cleaning kit. I've never used a firearm after applying WD-40 to it, and have only applied WD-40 to a firearm on a small handful of occasions.