We install and review all open source eCommerce solutions as a matter of course. So we have looked in depth at all the one mentioned here. I prefer osCommerce to Prestashop. Prestashop is too immature and simply does not have the in-built functionality or breadth of Add Ons. It is not a "lite" version of Magento by any means.
As to the other poster's comment about osCommerce and Magento. Magento is an out of the box solution which is very difficult to customize. You need to be a programmer to work with it and even then the learning curve is steep. And if you do customize, you then are buying out of their upgrade path. Which is why the average site does not customize and why so many Magento stores look so much alike.
Unlike Magento, osCommerce has and always will be intended as a core eCommerce solution on which you build you own unique eCommerce solution.
Two different approaches to building an eCommerce site. One is cookie cutter then other is fast track to custom solution.
