Dota 2 is much harder to play and master than LoL, this is probably the main reason why LoL it's so popular...it's easy to get started and average/hard to master.

Either way, I've played Dota 2 a year ago and the game is great, you don't have to buy heroes, runes, pages, so it kinda removes the Pay buttom and focuses entirely on the gameplay. Let's just say MOBAs are not really my thing but I enjoyed playing a couple of games every now and then.