e-commerce platform

I currently have an eBay and Etsy store that sells vintage knits and crochet patterns in PDF. I'm looking to get away from Etsy and set up my own store. I will be selling digital downloads. What is the best e-commerce platform to use. What do you advise about the use of EKM? I read that EKM has the eBay integration. How does this work would it be the same as downloading a CSV file? Thank you