If you can gather 1 to 3 people for local multiplayer, then feel free to buy this game.
However, if you plan to play this game by yourself, make sure you have a spare controller before purchasing this game.
Why? Because even with a keyboard, a controller is required to play Versus mode, and certain content (at least 3 map sets and all 4 extra characters) can not be unlocked unless you can access Versus mode.
If you do not have a controller, you will not be able to unlock all single player content.
If you do not have a controller, you will not be able to unlock all the content in a game you paid for.
I would change my stance on this game in the future if either:
1) The ability for a single player to fight against the AI in "versus mode" is added
2) An online mulitplater mode is added
The second option may be a little unreasonable, but the first isn't.
Either of these would allow players to play versus mode without a controller, thus giving them the ability to unlock game content that is currently unaccessible with just a keyboard.