Just started playing a few days ago, quite interesting. Totally different to any type of strategy game I've played before (Starcraft, Warhammer, etc)
So far, I've played Omniknight, Lich, Axe, Dazzle and Jakiro - the first two are probably my favourites for now.
Last hitting is so hard #firstworldproblems
Professional gaming seems a bit silly to me.
In what sense?
You should see the Starcraft scene in Korea - craaazy
Gaming is becoming more and more popular of a hobby these days - gamers are no longer looked on as the nerdy type of people who can't say more than three words to another person. Naturally, eSports will flourish more as time goes by.
I did watch one Dota game, NaVi vs IG from the International 2012, the one that ended in like 30 minutes. Didn't get a thing the casters said.