In order to build a powerful eCommerce system, which system or framework do you recommend and why?
Magento, OpenCart, Drupal (eCommerce distribution), Prestashop or something else?
definitely magento especially community version. With help of it you can build any kind of shop, but you need a team of devs for it. DO NOT purchase any themes for it(mostly they are total crap), create one by your own.
It's hard to judge without knowing what does business want to do? What’s their short/long term strategy? What’s their existing technology ecosystem inside the organization? How much of business appetite they have? How are their technology strength? And there are a many more.
Hello, you can find some useful information about wht Magento and how it compares to other open source platforms in these blog posts below:
Hi Omid - Can you share with us more details about your project so that the community can better understand your needs and what you're looking to accomplish?
What you've asked is a generic question, and an equally generic answer will actually be of NO help to you.
So you might want to elaborate your requirement a bit in order for someone to be genuinely help you.