I've played LoL for a little over two years now, WC3 Dota for about a year and a half back in 07, and have recently gotten into Dota 2, which I've been playing for a little under a year now. I've had a very short experience with HoN, which actually isn't a terrible game, but since it was basically meant to offer the gameplay of Dota without the limitations presented by the WC3 engine it's hard to recommend it now that Dota 2 is out (although HoN's matchmaking is a bit better). Having a good amount of experience with the two I can very confidently say that Dota 2 is far, far better than League of Legends. Firstly, Valve is a much better company than Riot, and Icefrog pays more attention to his fans and works harder on his game than almost any other dev out there. This may not seem too important, but in this kind of RTS it's a huge deal. Character balance and content based around community feedback is absolutely imperative to having the game flourish, and in this regard Valve absolutely trounces Riot. For example, a few years ago in League of Legends, stealth characters used to be insanely strong, so to 'balance' (it's hard to even use that word in this context) the game Riot severely crippled the game's stealth characters. They had promised a fix, but, despite the community's feedback regarding these characters, they didn't get the fixes they were promised until well over a year after the fact. Valve, on the other hand, implements fixes within days of getting community feedback. You find Riot hard pressed to work on anything that doesn't directly earn them revenue, so while they're laboriously churning out overpriced characters to sell you every two weeks, the characters that you already bought go unattended until years after their issues have been brought forward. Secondly, the games themselves are like checkers and chess. Even a knowledgeable LoL player will agree to this, LoL simply does not match the demand for strategy, cleverness, critical thinking and reflex that Dota has, even in the highest skill brackets. Riot even openly admits they omitted the more complex mechanics from Dota from their game because they wanted their game to be more accessible, and while that does make the game easier to newcomers it ends up playing more like Smash Bros than an actual strategy game. Of course, it's true some people prefer this. Even I have to admit that League of Legends was not anywhere near as tense as playing Dota is. This makes it an easier game to just kick back with, relax and talk to friends over a 45 minute match, but when it comes to providing a deep, complex challenge, League of Legends simply doesn't hold a candle to Dota. It's worth mentioning a few things before wrapping up this post, such as Riot's insistence on selling characters. Valve does not do this, in fact everything that affects gameplay is included in the game from the start, all you buy are cosmetics. LoL is a different matter, you have to buy your characters, either with real money or in-game currency, which, if you play the game a lot, you can earn enough to pay for a new character every two weeks. If you're just playing casually this isn't too much of a problem, you can just grind for a character that catches your interest, play them, and grind till you get another one. If you want to improve your skill as a player, however, this is severely limiting, as you simply will never have the flexibility to pick/counterpick an optimal lineup every time. Riot does manage to mitigate this problem somewhat, however, if only in that most characters in LoL play relatively similarly, especially compared to either Dota or HoN. So unless you're planning on just playing an easy going game that never really tests your strategic skill, you're better off with Dota.

Dota 2. But I don't have any experience with LoL or HoN, and Dota 2 is my first MOBA game.

They're both terrible.

League of Legends because... my computer runs DOTA2 at around 4 FPS and crashes after around 5 minutes. Also I'm getting much better at LoL. I went 8-0-9 today which was awesome. It was probably my best game ever.