It is vastly superior to Okami. Okami was a very good Zelda knockoff, while Valkyria Chronicles is an excellent and unique strategy game.
VC has excellent art direction, and a compelling story. Also, the game play style is unique in that you move people around like a 3rd person action game, but the game is really a turn based strategy game. It is more than challenging, but provides a good ramp up in difficulty from the start. Also, the game will last at minimum 20 hours, and I think I took 35 hours and I still have a tiny bit left of un-played content.