Bought the deal and I am pretty happy with it. I've heard about Publishdrive on Joanna Penn's podcast for authors many times and there is a good interview there with Kinga, the CEO. Basically there are a lot of Google SEO benefits to being in the Google Books store and these guys make it relatively simple. That's in addition to getting into a lot of other stores, in print, and libraries. It's a 'wide' approach to distribution that you don't get if you just use KDP/CreateSpace from amazon.

I think the key thing here is that publish drive does the distribution piece for you. After all, if the book isn't available where they want, then your readers won't buy it. This way you can focus on writing and promoting your book(s). All in all, looks like I'll be really happy with this one.