I used to be a fan of Fictionwise but now I buy most of my books from Amazon.
Take this book for example (Dragon Champion by E.E Knight):
http://www.fictionwise.com/ebooks/b72628/?si=0
Even with this 25% off giving you a price of $9.45 (not club) the regular price at Amazon is only $0,54 higher ($9.99).
One other thing I've noticed about Fictionwise lately is that they more or less dropped the support for secure mobi on a lot of the books, pushing hard for Secure eReader format.