To put it simply...
This game has serious flaws but it's also amazingly fun and addictive. On top of it all is a tightly-nit, active, friendly community. If you play for any length of time you will get to know all the active players (and I do mean -all-).
I've played DOTA, HoN, and Demigod.
I dislike HoN, it's boring and uncreative. DOTA is fun but outdated. Demigod is a new take. It's got a small amount of heroes that are very well developed.
The main downside with this game is the frequent bugs, crashes, and other errors you will run into. But it's worth it, especially considering this game is only $5.