I do not recommend ChannelAdvisor

In my opinion, you should save your time and money by choosing Zentail, or at the very least, Sellbrite. From my experience, ChannelAdvisor's salesmen will lie to you and tell you whatever you want to hear. Once they have you signed up for a contract then they have access to your bank account. In my case, they took money out twice more than necessary, with no notice or explanation. I was not able to get anyone on the phone and received no responses to my emails. Onboarding took double the time they told me and I was not able to just list a new product on my own.