Level 30 summoner at the moment =D
Well in my personal opinion i think LoL is actually more fun than either HoN or DotA cause of one thing. The Barracks (Inhibitor in LoL) respawns! I think this feature actually gives players a chance.. no matter how small to actually turn a losing game around.
In DotA if your rax is down, u can kiss that lane goodbye.
And runes actually make very little difference unless you jungle a lot (Warwick / Udyr). Their there to give u that extra little edge against other players, plus you can only buy runes using IP, which is gained through playing a lot. So the game rewards you for spending your time playing.
O and LoL towers actually do something... Play HoN / DotA and see how much tower diving you see.