Apparently, if you want speed of publishing process use the B&N Nook book publishing platform; if you want greater sales (but with slower publication management processes) use the Amazon Kindle book publishing platform.
At least that is the conclusion of Allen Harkleroad in this article from the Statesboro Business & Lifestyle Magazine:
Amazon Kindle Versus Barnes and Noble Nook Book Publishing - Six Months In and Kindle is Winning
With all the brouhaha over the Barnes and Noble Nook reader, I tested the publishing side to determine if either has a monetary advantage over the other. I am a self-published author with more than fifteen books and guides under my belt. Most of my books are available in print as well eBook formats, so for me the idea of testing sales of books on both devices was intriguing.
I have ten ebooks published at Amazon’s Kindle Direct Publishing and at Barnes and Noble’s pubit. The process of adding new titles was faster and more streamlined at pubit than at kindle direct publishing. The books submitted to pubit appeared in the Barnes and Noble online catalog more quickly than the titles submitted to Amazon direct publishing. I am afraid though, that speed is pubit’s only advantage over Kindle direct publishing.