Hi JM I see what you are saying.

To go even further the UK stats would show that some popular genres in the US like Country and Christian/Gospel barely register as a percentage of sales.

Back to the original question I would never use a pay critique service for the following reasons.
1. I am an experienced writer and have many well respected friends in the business who would gladly provide constructive criticisms that I can trust for free.
2. Most of the critique services operate in music genres that do not relate to my style of music and writing and are not aquainted with the music scene in my area. Therefore the opinions would not be worth much.