It is clear where Google intends to take the e-bookstore: Mobile and Chrome. The store is optimised for Android, embedded into the Android Marketplace. On the PC, it shares the characteristics of a Google webpage, with the traditional Google search and page system. Each book has review data, elegantly sourced from Goodreads, which adds review data to the bookstore without having to create them from scratch.
On the PC Version, purchased books are stored on the cloud. This means that problems as DRM restrictions on accounts and devices are avoided. It does mean the PC needs to be attached to the net in order to read (more on this later). On the Android version, the books are also read from the cloud, but can be downloaded for offline reading. The downloaded book is hidden to the user, and our attempt to locate the book on the Android file system failed. So the DRM is not as in your face as other schemes.
You can download books for offline readers. The book formats are PDF (for the scanned books) and ePub (for traditional ebooks). The DRM used here is Adobe, so you may need to use Adobe Digital Editions. As a DRM, ADE is proberbly the widest deployed, with readers like the Kobo, Kogan,Sony and many Chinese OEM devices using the Adobe DRM. ADE is also available on Windows, PPC and Intel Macs. MAny (but not all) should handle Adobe PDF DRM files as well, however you will need to verify this.
The vendor side is handled by Google Wallet, so if you have a Android device, it is already built into your Google Account. There is no other choice (eg Paypal) so you need a Credit or Debt card that uses the VISA/Mastercard ecosystem (most banks will support these cards).
The range is not as good as I would expect. As mentioned in our first look, many books available on competing sites are not available. Google eBooks will still come up with details of a book, but will advise it is not available. My testing book (A chick Lit scifi book that was available on numerous sites called An Accidental Goddess) does show when searched, but it does have 'I want this as an ebook' button, so there may be user demand to include some books or genres in the future.