Some time back I did a review of various web shopping carts.  In particular I needed a cart into which we could integrate a minor, third-party payment processing system.  We also wanted something that had the following functionality:

1. multi-currency
2. multi-lingual
3. registration management
4. mailing list management

These are the carts that I found in the order they were discovered and reviewed.

APIs and Frameworks

Started on the assumption that we would want to build and manage our own shopping cart.  It quickly become apparent that a customizable stand-alone application would get us more functionality with less mucking around.

• Webforce Cart
  Very simple shopping cart class.  After a quick review, decided that it would be better to use something inside a framework like Cake or Symfony.
• sfShoppingCart
  Shopping cart module for Symfony.  Played around with this but quickly realized that, even in a framework, maintaining a custom cart would fairly troublesome for my simple needs.
• phpShop
  Another simple, rails-esque cart.  Seems to be a framework built specifically for the shopping cart.  Would still probably use sfShoppingCart over this.
• Quick.Cart
  Very nicely done, simple cart.  Installed and played around with it a bit.  Difficult to modify the layout; template updating problems.

Stand-Alone Applications
Lots and lots of apps out there.  I was surprised, however, to discover that many of them are branches of earlier code bases.

• Nexternal Solutions “Ecommerce Shopping Cart”
  Aggressive Google advertising.  Ugly.  ASP-based.  No way.
• osCommerce
  This has been around a long time; looked at this originally five years ago for another project.  Lots of web shops out there using osCommerce, but developers complain that it is difficult to integrate and maintain.   Admin interface looks like it needs work.
• Zen Cart
  Fork of osCommerce and, now, possibly the most famous open source shopping cart solution.  Installed and mucked around with it.  Confusing, clumsy interface, though better than the osCommerce original.  Lots of complaints from developers.  Many recommend switching to CubeCart.
• CRE Loaded
  Another Fork of osCommerce with a corporation behind it.   Nice marketing website.  Same poor admin interface.
• osCMax
  Yet another fork of osCommerce with (maybe) Drupal integration.
• xt:Commerce
  And yet another fork of osCommerce.  Corporate backing like CRE Loaded.  Seem to be pursuing global distribution; based out of Germany.  Spanish version on the way.
• Miva Merchant
  Looks as though this might be the most “enterprise” of the shopping carts.  Starting price:  $995.00.  Pricey.
• X-Cart
  Comparable to CubeCart but no free version.  Lots of complaints that cost of additional modules rapidly builds up.
• AgoraCart
  Nasty green interface.
• Squirrelcart
  Weird.
• phpCart
  Looked great, but seems to have been replaced by PHP Super Cart which appears to be… even yet another fork of osCommerce.  Ugh.
• CubeCart
  Good reviews.  Open source and very reasonable commercial models (one-time payment as opposed to recurring  licensing fees).   Easy to localize.  Good currency manager.  Stylesheet-based templates are a little awkward.  Very active development and fairly strong community support including skins and modules.

In the end we went with CubeCart.  So far it’s been “okay”.  Template organization is indeed haphazard; it can be difficult to figure out which templates apply to which step in the purchasing process.  Documentation is also fairly thin on the ground.  And though we paid for support, the replies that come back are fairly unsupportive.

Nevertheless, integrating the third party payment system was not too difficult.  I can recommend CubeCart.. with reservations.  Look around for your own alternatives and settle on this if it seems suitable.