It's 39.99. Between the added characters, new endings, and tweaks, I'm happy to buy it at that price. If it was a full priced game that would be a lot more iffy.
I figure if the characters were DLC with the number they've announced (we're at what? 9 - Dudley, Ibuki, Juri, T Hawk, Guy, Cody, Adon, Dee Jay, and one I'm forgetting), that's basically the price of the game right there.
Also - BONUS STAGES!!!!