I have been working on DanDomain Webshop software as early as Feb this year and as the project is drawing nearer to an end, just thinking to leave some thoughts here as compare with Zen cart and osCommerce.
Before I start, I would like to emphasize that this is solely based on the view point of a designer regarding the template system and not on a standpoint of an owner. Why would I say so? Well, for owner or anyone else who wish to open a webshop and start selling right away, webshop v5.5 is a good start, simply because the ease of use as most of the settings are controlled in the admin panel. There are a number of default templates and styles that one can set easily with very little knowledge of html programming. As far as I can see, this webshop is rather popular with its Danish clients.