Here is a very comprehensive review to a bunch of budget lights (including the RC-F4).
http://www.candlepowerforums.com/vb/...d.php?t=202032
I have an RC-F4 and it is great. I wouldn't consider it for tactical purposes because you must fully click the switch to turn it on, but for a really bright light that you don't care if it gets messed up... its perfect.
It definitely isn't near the same quality as a Surefire (all you have to do is hold both in your hands to tell that), but it is probably one of the best values available.