its very simple, Riot decided to make their own game while HoN is just a copy and paste version of dota. Which is the reason its going to die when Dota officially released but league of legends will keep going strong.

You know, despite all the **** HoN gets, it's still gonna be the #3 MOBA for a very long time.

I find the interface really clunky and awkward

HoN has a lot of weird carryovers from the WC3 engine that drag it down.

LoL went its own way and made itself a lot more accessible for someone who's never played the original (or never really understood what they were doing the handful of times they played the original).

Personally, I also think that League's graphics are also miles better in terms of clarity. I tried out HoN, and even though they graphics were prettier, they're kind of bad at communicating things to the player, and the heroes and creeps blend into the environment.

Well here's how LoL won my heart:

My friend invited me to my first LoL game, I had no clue what I was doing but I appreciated the fact that it was free. I started learning on Cho'Gath and found him very fun to play and he quickly became my favorite. It took me awhile even on LoL before I could become self sufficient at learning how to build champions and not play like a !#@$ing ****** but I got there and really started enjoying the game. I learned that there were other MOBA games out there namely HoN which everyone seemed obsessed with. I looked at a few videos of HoN gameplay and quickly decided that it wasn't for me.

I looked up some youtube videos and found some guy playing this champion that ran around on all fours very wildly. It looked like it'd be difficult to control just because of the animation. I'm sure the controls must be similar to league, but it just looked so messy that the fact didn't register. I saw him buying items in the shop and saw that there were what looked like HUNDREDS of items. I had no idea how i'd ever manage to learn to use them properly. It was also horribly organized. The graphics were smoother, but the HUD looked like it was 10 years older and the graphics blended into everything. In league champions, towers, and minions are all clearly discernible. In HoN movement is pretty much the first thing you notice. When it came down to it, I didn't want to have to pay $30 for the mess that I'd seen.

From my perspective here's how the games stack up:

LoL:
Free
Simpler itemization choices
Very clear and sharp graphics
Friendly user interface
Much more appealing champions that feel more unique

HoN:
Pay to Play
Unbelievable numbers of items in a poorly designed shop
Muddy hard to read graphics, which while less cartoonish are far more difficult to use as a player.
User interface looks like LoL's from beta.
Champions seem ill defined as unique characters.

Edit: In fact my experience with HoN has even made my choice with DotA. Since I heard they're almost the same game, if DotA is anything like HoN I really don't want to play it. I appreciate what makes LoL unique and I enjoy what they bring to the table as a game. I don't care what came first, I care what is best for me as a player. I feel like LoL is more down my alley so that's what I play.