I’m not a big fan of the star ratings. They are highly skewed by factors such as how easy it is to submit, how hard it is to get a track accepted, how friendly the contact is, etc. and those factors may or may not be the most important to a given person. (Not saying they are trivial).
Of much more value is to filter by category such as exclusive vs. non-exclusive, RF or not, etc. That will help you narrow down your list and begin your research.
Different libraries serve different markets. For example, Crucial Music is non-exclusive but generally caters to a higher client base and gets sync fees. Other non-exclusive libraries primarily pitch background cues for cable reality TV shows with backend only money. And then the RF market is totally different. A rating without an understanding of the market the library serves doesn’t tell you enough.
Good luck!