Pros
Their researchers and editors are skilled at getting your stories placed, however, YOU WILL NOT BE PAID FOR YOUR WORK.
Cons
I was contacted by a researcher in 2018 who was eager to place a series of my images. He did a phenomenal job. My images ran in more than a dozen publications. A year later, however, I am still trying to get paid.
I hesitated about working with Caters in the first place. A quick Google search shows there are lots of freelancers who have had trouble getting their money. The researcher, however, promised me that those were old reviews and that Caters has fixed its payment issues. Unfortunately, it has not fixed its payment issues. While they do issue timely royalty reports, it appears to be impossible to get paid. Payment requests are acknowledged only with an automated reply. Even when you ask someone to contact you, nobody does.
I know my experience is not unique. Several photographers have sent me emails after seeing my Caters byline, asking if I ever got paid for my work.
There are lots of agencies that do the same thing that Caters does. Save yourself the trouble and use any of them.