I purchased it after seeing a preview on ImpulseTV; it's a GREAT, and very fun game! At 10$, it can't be beat. I recently scheduled a multiplayer match, for Thursday and got 4 players (5, if you count a switch from one player who needed to leave to a new one) and it was very fun.
I strongly reccommend this game, though I should also mention that in some MP games, going to heavily defensive is just as big a mistake as any other RTS. Specifically, in 'wars' you gain income by sending creeps at the enemy, and loose it to upkeep as you build towers. If you overbuild your defenses, you cripple your economy, and that can be devastating.
Still, overall it's a great game!