Buy! Cheaper than iTunes (and usually cheaper than seeking out CDs, for that matter) but Toby probably gets more money out of it because you're buying directly from him without a middleman or three. Plus some very hard to find stuff has just become very easily available. Bravo!
This is very cool, as Banco de Gaia is/are pretty awesome. I have Igizeh, which is a very good album.
Incidentally, "I Love Baby Cheesy" from The Magical Sounds of Banco de Gaia was featured in a car commercial about eight years ago, which is a random fact that is (probably) only interesting to me.
Edit: And as much as I am lamenting the loss of the "brick and mortar" music stores, I can't help but think that the trend towards artists-established digital music stores will benefit everyone (save the music store owners and the labels) in the long run.