Any gun owner that doesn't know should turn in his man card, or at least his gun card. It's somewhat spendy, but so are most name brand chain lubes so I can't say for sure which costs more.
Yea, I know, another oil argument. I can't say whether it's a superior gun lubricant in long term use/abuse to regular oils, but it makes actions feel very slick and it has cured many people's gun problems. I've had many people at the desert spot come to me with cycling problems and don't recall any that weren't cured by One Shot. It also seems to make them easier to clean. It even cured the guns that were stopped by Frog Lube. I try to always have a can on shooting trips and when I forget I'm reminded why I bring it. I've used it on many other things where I don't want a wet lube.
There's One Shot case lube and gun lube so make sure you buy the right one for the right purpose, the case lube is also great. I've never used Imperial or any of the other supposedly great ones so I can't say for sure that it's superior, but it's easier to apply, particularly for large batches/progressive loading, and works very well. Being a cheapskate I've moved toward DIY lanolin/alcohol for big batches, but still use the OS for small runs. I think the case lube is what made me try the gun lube.