Shadow Horse

I've been using this app for at least 5 years. It works simply and effectively, with lots of flexibility to tailor the synchronization options to your needs and accounting set-up. Whenever I've needed support, it's been excellent with very fast turnaround. Dave, Nick and Rods have been particularly responsive and helpful. Highly recommended. Oh - and it's free!

Switched to Shopsync after the fall-out between Mailchimp & Shopify. Set-up was very simple and all seems to be working as it should. Worth looking at the article on Mailchimp giving instructions on transferring from their own app to ShopSync which is very helpful.