My ratings are, as probably anybody's here, highly subjective, but probably through every new listening experience get a tiny bit more objective.
This is my rating system (mainly for my own orientation):

5.0 - Of Highest Importance (very subjective, mostly autobiographical ratings, but sometimes in accordance with the historical rating)

4.5 - Outstanding

4.0 - Very Good

3.5 - Good

3.0 - Almost Good

2.5 - Satisfying

2.0 - Problematic

1.5. - Very problematic

1.0 - Unlistenable

0.5 - Noise