It's okay. There are more than 13 episodes. If you're buying it, you can get Stages 1 & 2 (both seasons) from this website for $60 (it apparently normally costs $175).

It was a blind buy for me about a year ago for about the same price, and I didn't hate it. I probably wouldn't have bought it if I saw it already though.

If you're looking for something 'new' though... Vandread is about 8 years old.