When it comes to MOBA's it's all about what the majority of your friends/Social circle is playing at the moment. At one point all we did was play DotA 1, then HoN until Dota 2 came out to take back the crown, it was League of Legends at another point but today it is HOTs (Heroes of the Storm -- made by Blizzard).

Solo queuing on Dota 2 just isn't as fun now since the community has become so big a lot of toxic players are just coming out of the woodwork. Pretty much on par with the toxic League community, and even HOTs is starting to get there (and that's the most casual MOBA out of all of them.... smh)