I play it on occasion. I haven't got too into it, as my graphics card fails big time. Still runs, it's just laggy as heck and the textures look worse than poo.
I'll hit you up if you wanna play sometime though. What's your prefferred difficulty?
I tend to not take the game seriously. If you ever watch Kilplixism or Criken, that is usually how I play. In versus, I tend to be a little more serious, but not by much. Basically, I'm fun to play L4D with.