I've been playing a bit of LoL. And I had played a bit of HoN too. In my opinion, I like HoN the least, and Demigod and LoL both have their merits.
My biggest beef with LoL, the Ultras being too powerful, has been scaled back it seems. You don't drop in a single hit anymore, which makes for some more interesting skirmishes.
There are 2 other things I like about LoL. The Meta game with persistant 'summoner' levels, Runes, Talents, ect. It's a nice costimization option. The other thing is that the Creeps are mroe then just Fodder. They'll do signifigant damage to you, they take more hits... There's is just less of a varaity compared to Demigod.
Then of course Demi has all the things that make it uniqe, Flagging, Favor items, upgradable creeps, more robust and Specable heros. (LoL heros will always have the same skills no matter what at max level.)
I would like to see Creeps be more of an obsticle in Demi. I havent tweeked with the game options for it much yet, but maybe if there were more options for it too. I know you can make them stronger, but then you'd have to make the towers stronger too... Can some more additions to options there be made?