I was accepted into Amazon Handmade when it first launched but after reading the terms and conditions I never pursued it. They enforce white backgrounds, no watermarks which I could live with since the audience is much larger. But you can never have the product on another platform priced more then Amazon. The fees are alot higher. The expected service turn around was too short so it worked only if an item is ready to ship at least for me.
I tried others but Etsy, word of mouth and social media works best for how I like to manage