Is the RetailRocket SaaS service efficient?

Question

Electronic commerce

I am engaged in B2C sales in the field of home goods via the Internet.

I recently came across a service called RetailRocket, which supposedly personalizes offers for customers, thereby increasing their LTV and optimizing CAC. Their main function, as I understand it, is to send out letters with the goods offered, depending on what the client bought before.

I have doubts about their effectiveness. Reviews on the Internet - zero to the mass, cases can now be drawn on the knee. Has anyone worked with these guys and how can you evaluate the result?