I've had one for decades and like it a lot, and have used it quite a bit. I forget at the moment if mine is a Camillus or an Ontario but it's definitely GI spec, not a cheap copy.
I especially like the stone. It has perfect 90* angles on it and I've used it (don't laugh) to do quite a few 1911 trigger jobs. GREAT stone!
The sheath, with its slots, is flimsy compared to a "real" sheath with a loop. But I understand that's because these are sometimes sewn directly to flight suits and such.
The knife in its metal-tipped sheath would make a pretty good sap, if it had to.
I like the bolt-head pommel, which can be used as a hammer.
The saw back is just about useless on wood. I'm given to understand that its purpose is to rip/tear its way through sheetmetal, such as aircraft aluminum. Maybe that's true, maybe it's not.
For a long time I though the USAF knife was too short at 5", and the KABAR too long at 7". I wanted something at 6", and even designed a knife combining the best features of both.
I've used the KABAR quite a bit, too (mine's an Ontario, USGI spec) and am starting to think its 7" blade is about minimum for what I'd want in a survival knife. Another inch or two might not hurt. If it's going to have a saw back, I want the teeth "set" for actual wood cutting. I've seen Victorinox Swiss Army knives with effective saw teeth. Can I get those teeth on the back of my knife, please.
Truth to tell, I'd rather have three or four of those survival "string" or "cable" saws (with rings on each end) in my pack than any kind of saw teeth on the back of my knife, though of course having BOTH options on hand wouldn't be bad.