1. Because Valve never takes servers down like S2.
2. Crazy stuff, free dlcs, alot... Played Team Fortress 2? Crazy how much stuff you get.
3. Dota 2 uses STEAM, community, perfect! Blogs, news and more...
4. It has better graphic for sure.
5. Dota 2 is not Dota remake, its new game 100%, new heroes, new spells. Cant wait.
Valve keeps game alive, updates when something goes down and time. 90% PC gamers uses steam.
Oh and i like that i got steam and everything is there with dota 2.