So, as you can see, X-Cart Multivendor does not have all (actually, any) necessary tools for vendors, sales, promotions, regular customers, administrator. Even in the Ultimate version, it does not have any way to make automated payouts or manage a lot of vendors, so you will have to do it manually. That is why I am sure you can not make a big project with it.
CS-Cart Multi-Vendor not only beats its opponent in the number of built-in tools but in their quality and service too.