One thing that I have not liked about nopCommerce is the fact that I can't integrate with other solutions (like blogs, cms, etc).
My company Adept Web Studios has developed a new customer provider for nopcommerce that stays in sync with asp.net membership. It requires clear text format and membership must be external. For example, I must have membership residing in another application or provider and have nopCommerce point to it. Not vice versa. I was able to get BlogEngine.NET working with this nicely :)
http://cid-3637afd2bcaa0a57.skydrive.live.com/self.aspx/Public/AspNetCustomerProvider.cs
