Warning! Wall of text ! You are warned

Yes I've tried HoN. Personally, I don't like a game which is almost 80% ripped off of a game. Why pay money for a new game where you can already play it free ? You may say the graphic. But.. really? Not me tho.
However, HoN do have something that is better than LoL.
Gameplay wise, it very much like dota ( its a dota ripped off anyway). However I discover something different in it. Not really obvious if you did not pay attention. It is the attack animation and the projectile speed of the game is much faster than dota. I played the zeus-like heroes and I realized that it is much easier to last hit and deny.
Besides that, I like HoN top left HUD which display the skill condition of your team mate. Whether your team mate have their ulti cd-ed or not you can c from that HUD. Its convenient. Moreover, you can use ur item in your inventory using keyboard shortcuts alt+q,w,a,s,z,x, which is nice.
Net code I heard that HoN is better and I cant comment on that since I'm not familiar with net code

Do note that all the advantages that I listed is how user friendly the HoN interface is but not how fun the game is.
IMO its all boil down to own preference, I prefer more orginality when it comes to new games. For me I will prefer LoL because there is more originality such as the rune system, masteries, summoner spell, ability power, neutral buff and the super creep mechanics.
@Deimos Tel`Arin
HoN is easier to pick up? Nahh.. its only reflect to those who are experience to dota. Ask a new player to try it, can he pick up quickly? I don't think so. To me, both have large learning curve (for new player) but LoL simply wider.