If this is random encounter, I'd say The Comedian wins... He's a very shoot-first-ask-questions-later kind of guy... Joker isn't exactly great when it comes to H2H but The Comedian can hold his own against Ozymandias(who, in my opinion, is on par with Batman in H2H).... Joker wins if he's prepped, but I assume this is random encounter so... The Comedian 9/10...
Any weapon used from any previous comics? Joker slaps on the mask and reality stomps the comedian into oblivion.
If we're staying strictly cannon then it's pretty much whoever shoots first. Comedian will kill in one shot with a gun, unless Joker gas hit's him first. I'm sure people will disagree but I don't think the comedians reflexes are much higher than Jokers if at all. Stalemate for me unless someone can convince me otherwise?
@Joygirl: I've seen you in a few Joker / Harley threads I think, do you have any good scans for Joker reaction times?