League of Legends is an easier and more accessible game, but has a worse business model. You have to buy individual characters (and stat increasing runes) in League, whereas the entire character pool is free in Dota (plus you can get

HATS

to drop). If you are brand new to MOBAs I would recommend LoL and suggest Dota later on if you get bored or want something more challenging.
Both games have absolutely putrid communities that will constantly bitch at you for making the slightest mistake. Thankfully, they both have bot matches where you can play against the AI and people generally less critical there.
I don't play League any more (primarily due to the endless grinding) but if you want advice or shit I'm usually on Steam. (same user ID as here)