I get why I'm liking League more than DOTA2 at the moment.
I like playing Support. It's not very stressful, and you can help your team mates by making sure they get to do the killing and the enemy team won't do any killing. Or much. Sona is amazing because she can provide so much! (I like Lulu too, though!) Having spellthief's edge and the appropriate masteries mean your gold income is just fine, especially if you poke/harass a lot.
When it comes to support bot, a good support makes or breaks the lane, I feel. At least, whenever I play bot lane, I'm more threatened by enemy support than enemy adc, regardless of whether I'm support or adc. As support, I make it my job to be as annoying as possible and bully the other support (and adc, god willing!) out of the lane.
In DOTA2, support doesn't feel nearly as rewarding, and you hardly have the item slots or even gold to really get rolling unless your team is rolling.
For the foreseeable future, I think I'll be playing League of Sona whenever I feel the MOBA urge.