Hi Sam,
I probably wouldnt bother with any of the platforms that specifically review SEO companies, more often than not they are filled with "Paid" or "influenced" ratings.
Reviews in general for this industry in my opinion should be taken with a pinch of salt. That being said, if you have a review for a company then id almost always recommend the major review type sites that cover all businesses like Trust Pilot, rather than one specifically aimed at a specific niche where coverage is likely to be low.