I've never played HoN only looked at videos, didn't like it. At the time there was no dota 2 and it felt too much like dota 1 ripoff. When I got bored of dota 1 some friends went to play League, I joined for about a year. It was better graphics after dota1 but the mechanics and community of immature kids made the game stale quite fast.
now that dota 2 is "out" I'd have to say I do enjoy it quite a lot more than League. The community still has problems but it's a lot better than dota 1. For example, there's been like 3 leavers and there's been like 1 game when support didn't buy courier out of over 200 I've played. You still get bad games where the skill gap between you and your allies is tremendous, but it does seem like there's a lot of people who are playing dota for the first time and still trying to learn, so I cut them some slack instead of flipping out on them.