This is by far the best time sink I have ever spent money on. With a very scary learning curve that needs perseverance
I have never spent so much time on a game before, it is by far the most worthy game for your cash, but it is not for everyone. Any casual gamers stop reading here.
To play HON you have to endure a minimum of 3 weeks of rage from the community (that is a given), previously playing DOTA helps but still expect some fury from this anal community. Once you have passed this trial by fire HON can become the most addictive game you will ever play.
HON is a M.O.B.A or multi-player online battle arena. Its game play consists of choosing a hero and duking it out in an arena with the opposing team with your teammates. As you play you will need to purchase items to increase your heroes abilities and certain items are better suited for certain heroes, because of this to be an "adequate" HON player one must memorize each heroes abilities and core items. With 70+ heroes and 40+ items this may seem like a daunting requirement, I refer you to my rule of 3 weeks. There tool tips and a recommended Items lists for each hero in game so it is easier to get into than most other M.O.B.A's. There is also a tutorial mode but I think it is best to learn through experience and reading a forums is almost a must to excel in this game.
The heroes are balanced despite the views of everyone on imbalanced heroes, and one must realize that new heroes (roughly released once every month) require balancing every time. S2 (the developers) put a lot of effort into this game and the constant updates reflect that.
(note: Hero balancing is subject to S2's review of professorial players use of such heroes, and I trust they leave certain alleged imbalanced issues for a reason unknown to the normal player.)
People say just play DOTA and that is a legitimate option, however HON has several features that make it worth your money. The reconnect system allows so many games to be rage free (as much as the HON community is concerned). The leaver system also helps more dedicated players enjoy (in all intents and purposes) a G.G. The customizable hot keys are also a great aid, and the flexible UI allows for some great modifications to be added to increase your potency as a player.
HON is also a once payment game,you do not pay to win unlike another DOTA clone cough* cough*. There are alternate skins and taunts you can purchase , but they do not give you a significant advantage unless one counts psychological warfare an issue (taunt kills can cause an intense amounts of rage).
With DOTA 2 coming over the horizon one might think HON is not worth a purchase but I think it is definitely worth your money as getting into DOTA 2 may require some M.O.B.A experience with HON being the most refined on the market.