Mhh i think HoN has a perfect Usability. A lot of really nice Features just around the Game. Like the Option to reconnect in a Game if u disc. Demigod has bugs instead ... Invalid Gamestats as example.
HoN is much faster, I would say u have better Options for skillfull Play ... but not sure im not Pro in one of this Games.
The low count of Heroes is really another Problem. The Matchups are offten the same ... .
For the 2 new Heroes, the developer need to much time. Think 20 Heroes for differnt Matchups would be good but at this speed they will be there in earliest 2 years :/.
The Items bought in Demigod are always the same ... HP ... HP ... HP.
I can never buy a dmg item or two because i need the space for Hp items ... that sucks ...
In HoN u can really use different Setups ... .
I like Demigod very much ! I like the style and the concepts (ok locks suck) but i think the game has no chance on the market 
HoN has as Dota a long Period of Evolution and has so a very nice playable first Version ...