Overall, looks good but two complaints:
There's a "sync" button available when I right click on the home page, but it wouldn't recognize read positions from my other devices nor save a new position to the B&N server. I know the server works because I could sync the same book positions between my iPhone and Nexus 7, etc.
The lag time going from a book back to the home page is much too long. The app looks beautiful but badly needs speeding up.
Not a bad start though. I hope to finally see something in the Mac App Store updated for Mountain Lion as well.
And.... we're still waiting for Windows Phone apps.
Good start but I miss bing able to add notes and comments to what I am reading. This is my biggest reason for using ebooks.
Also, when turning pages I have noticed it will duplicate some of the text from the previous page on the current page. This only seems to happen after a refresh.
Also, can not wait for the Windows Phone 8 app.