I've been using CDP for several months, on a bigger package. This is my experience after several months of working with them so keep this in mind. The team I work with is managed by Sophia Monroe and she is really good at what she does.
First of all, you need to understand that, like with most content providers, you need to take some time to "train" them. Be clear in what you want, give them templates of what you want, improve on what they provide you. See if the type of content they're good at is suited for the type of project you had in mind.
After we got through the first month of working together, I understood what they were good at, the project I wanted to use them for and now we're working really well together. They communicate well, they respond quickly to my emails and request for calls.
I really recommend using CDP, but keep in mind that the quality is also related to the efforts you put in in the initial stages.