It has slower turning speeds, no free courier, and lots of little things here and there that yeah, make Dota 2 not so much of a fast paced gank and push fest as HoN has become.
I admit though that Dota 2 has better heros, items, and balance. HoN just has the better pacing, where matches rarely get over an hour long, but Dota 2, especially with no concede, tends to drag out.
They are both fun games. I pretty much only play HoN's casual mode now, to load up on items and levels real fast and enjoy some twitchy MOMA combat.
Dota 2 has all the potential in the world though, and with Valve behind it, ya'll best get to learning it well!