After having about two hundred ratings I had to rethink and use a more fine-tuned method:

5.0: flawless: not only a masterpiece record, but everything is in place, even the weak tracks/fillers are in place.
4.5: masterpiece: a milestone in the music history.
4.0: outstanding: a near perfect issue with maybe one weak moment, but definitely a strongly recommended record.
3.5: very good: an overall very good release with some weaker moments, listened mainly in special occasions, often hardly accessible albums.
3.0: good: correct release with some weaker moments, but worth to have it in the collection.
2.5: average: an album that is destroyed by some terrible tracks or terrible sounding/production, usually the "mistake" kind of albums of otherwise great artists.
2.0: passable: an album where you could find something interesting with patience, not a throw away, but something I hardly play.
1.5: forgettable: incident kind of records that are waste of time.
1.0: avoid: better not to try, you can save yourself from some unpleasant moments.
0.5: no words.

I don't rate music I don't listen, I don’t rate upon prejudice: i.e. you won't read anything from me about 50 Cent, Teletubbies, Cheeky Girls etc.