Hi there,
As per my experience and research you must look for these features in multi-vendor marketplace module.
1. Commission Management (Global wise or Individual Seller Wise)
2. Easy Seller List Management
3. Customized Email Templates
4. Visible Transactions For Admin
5. Multiple Shipping Method
6. All Types of Product Support
7. Multi-lingual & Multi-currency
8. Easy Product Searching
9. Huge Number of Product Collection
10. Easy Seller Registration Process
You can look for Magento eBay Marketplace extensions online but don't forget to match features list shared above.
I hope this helps!