With the earlier thread on magento, after some initial shock and confusion regarding the download size was cleared up, the general first impressions were positive ones.
To me the advantages of osCommerce, and why we made the strategic decision to customise and use it for the online shop section of websites created with our sitebuilder service, include:
1. osCommerce v2.x has a large existing client base of shop owners that have successfully put the system to use in many different areas, which shows that it is flexible, osCommerce and its contributions have already solved various problems and issues shop owners face, and generally it is doing something right (in the right hands)
2. With any software system that gets more complex with time, at certain stages you have to take a step back from adding to it making it more complex, and focus on simplifying the system and perhaps re-architecting for your future plans. This is what the osCommerce guys are doing with v3.x, they are re-writing it from scratch with a much better architecture, in order for it move forward - something that was definitely needed in osCommerce's case.
3. osCommerce v3, whilst the public-facing shop demos do not look very different, has a lot of differences under the hood, including XHTML, a much improved admin system, and other major improvements to the base system, bringing in some functionality that was previously only available as contributions, and adding new functionality.
4. When the much improved osCommerce v3.x is eventually released, you also have to ask the question what is the point of some of its derivative v2.x builds like Zencart and CRELoaded, which originally were there to address problems with osCommerce v2.x, problems that might no longer be there with v3.x
With our sitebuilder service we aren't worried about whether osCommerce is a CMS too, providing a cms for non-shop pages, since all of the non-shop CMS is handled by our sitebuilder cms. But if you are going the DIY route and want an online shop and a CMS for a lot of non-shop content, then osCommerce v3 alone still probably isn't the best way to go, and you should consider a Joomla and Virtuemart combination. Joomla provides the overall architecture for plug-ins, and Virtuemart is the ecommerce plug-in. Who knows perhaps someone one day will
integrate osCommerce with Joomla so it can fit into Joomla too.
Alternatively if you want a single system solution for both ecommerce and non-shop cms, with some imaginative coding, it shouldn't be too difficult to turn any open source ecommerce system into a cms for non-shop content too, by reserving one shop category within the shop for the non-shop content, not displaying the 'non-shop' category in the normal shop, but using its content (sub-categories, products) for your site's sections and articles content.