In my experience the game lasts 20 minutes, followed by 40 minutes of constant dreary dickery as the players repeatedly stalemate each others' attempts to finally win and finish the game.

edit: I haven't played Munchkin in 10 years, so they may have updated the rules somewhat.

It still works that way. There's a tacit agreement amongst my friends to call it after 30 minutes or so if no one has been able to win by that point.

Some of the variations can be fun to play (they add interesting complications to it). But only in small doses for me.

No it's still like that, it's a terribly designed game.

For some reason, Axe Cop Munchkin seems to be a lot more fun to play than regular Munchkin.

Yup, that is still the case in my experience.