I've got a sort of love/hate thing with DoTA; I started up on Random Allpick matches so I could get a feel for a variety of heroes, but quickly learned that it isn't too uncommon to be matched up against a lot of good heroes while your own side gets the crappy ones, and it doesn't help that the Sentinel always have their random picks first. Inevitably, in a game that I'm either winning or losing, people leave and the rest of the game is pretty much shot. So I've picked up more on Allpick matches and things are usually more enjoyable because, even if I'm losing, I'm having fun with a hero of my choice. I get discouraged by the poor balance at times though, how some specific heroes can easily nuke the hell out of anyone while others are more support heroes when nobody really likes to play support or backup.
I play other custom maps when I find the type I enjoy, Battleships is usually pretty cool, Hero Siege maps are entertaining for a while, etcetera. I've tried Tides of Blood a few times, and although I enjoy that it isn't a constant rush-nuke-flee fest that DoTA is, it's also discouraging to have such a lack of variety in the heroes, and the community surrounding ToB isn't the most friendly out there. Whenever I have some friends on, I'll join them for whatever maps they have to host because it's all usually a lot more fun with friends anyway.
Catch me on AIM, MSN, or in game, I'd be interested in getting some rounds of whatever going.