So far the time I have spent working with Mezzanine has been great. The code is very well written and understandable making it easy to dive in and make fixes and/or changes to suit your needs. Using Mezzanine's page_processors it is also very easy to add custom logic to any page you have created without having to modify the core codebase. The community around it is also great and very responsive, helpful and open to make changes to suit the needs of users.
Mezzanine provides all the basic features you would need in a CMS and then makes it very easy to add anything custom or unusual you might want. In this way you don't get overwhelmed by stuff you don't need.
I'm using both on Tindie.com (an Etsy for homemade tech) and love them. I looked at the other Django ecommerce platforms, and they are honestly no where near Cartridge/Mezzanine interms of usability and ease for the administrator. Satchmo is the best known Django ecommerce platform. It has a lot more functionality out of the box (shipping & payment modules come already integrated), however apart from that, it is a headache.
If you are looking for something that has the basics down (cart, product details, customizable payment system), Cartridge and Mezzanine are the way to go IMO
Do check out LFS - Lightning Fast Store, eCommerce Solution on Django - with Full front end too(jQuery)
Its one of the best Django solutions I've come across.
I've worked with other bigger bloated eCommerce solutions - Magento, Opencart, Zencart. But LFS is seriously fast. Clean, well written code and stable.
Does the LFS admin pick up other Django apps the same way Django admin does? Last time I checked that was the biggest problem with it. All of a sudden you need to give your client two different backend system for managing their site.
Mezzanine (and Cartridge) really go a long way in providing an enhanced version of Django's admin that's suited to handing over to clients, so your third-party apps plug straight in.
