I prefer ZenCart over osCommerce at this time because they have moved toward a CSS backed design, and to change the design/look of a site does not require changing the php coding.
Both osCommerce and ZenCart are database driven too. A database for your products and for your customer information. As far as customer profiles - both manage customer profiles, but the data is limited to mostly contact information, although customers can view past orders.
Not use Magento, have used Xcart which I think has more features than ZenCart or osCommerce.
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