I'm about 3 days new to dota, but am starting to really, really like the game. It's pretty easy to play and the recommended beginner characters have a very low learning curve (e.g. zeus, ursa). The game itself has a low skill curve, which means it's easy to learn the basics and get fairly competent with it in a short time despite not having years or hours of experience, unlike other games. Mastering it, though, will be immensely difficult as one has to memorise all the items and character builds to play competitively.

I'm playing Dota2 btw. Never quite touched the WC3 version- only played it once and decided I didn't quite like it, but oh well. :\