Its really difficult to say which one is best as all of framework have their own pros and cons.
Let me put some context and you decide
- Prestashop and Opencart are lightweight as compared to magento where as sopify is the easiest to use (If you don’t know much about coding and you don’t need many customizations this may be best option)
- Opencart does not Support Observer design pattern as magento hence creating module in opencart is painful
- Third third party module/apps integration is easy with magento as compare to others.
- Opencart marketplace is way to Good as compared to others.
Now its upto the user to decide which one is the best based on requirement.