DFY / Full-service / Amazon Automation

Hi everyone. I’m curious if anyone has any experience with full-service Amazon store managers. There are a handful of seemingly legitimate companies that, for a substantial cost, will start and manage your FBA/FBM Amazon store (including initial and ongoing product research, product listing, and all the other logistics) and will also receive an ongoing cut of the net profit. As someone who doesn’t have time to play the Amazon game myself, but who wants a slice of the ecommerce pie and who has the capital to invest, this looks like an appealing option. I’m interested to hear if anyone has first-hand experience with such a company, what were the pros and cons?