Quote from SkjalgFrieChamp,
My experience is that whatever moba you start out with is most likely going to be the one you'll stick with
I'd wholeheartedly recommend dota 2 of course, especially because its made by valve<3 and not Riot.
I played LoL for about 18 months then got annoyed at all their bullshit patches. I moved to DOTA2 and I much happier on that side of the fence. The learning curve is certainly a lot higher though.
I still play LoL rarely.