Foul:
0/5 - entirely worthless, offensive and difficult to listen to
Unenjoyable:
10/15 - pointless, bad, but not offensive
20/25 - leaves a poor impression, very few redeemable moments
30/35 - does not impact me as a listener, usually a waste of time
Passable to Decent:
40/45 - passable, does not leave a lasting impact
50/55 - average overall, or a mixture of great and poor moments
60/65 - gives me a sense of personal enjoyment
Great to Incredible:
70/75 - impressive, thoroughly enjoyable
80/85 - essential listening, worthy of attention
90/95 - amongst my favourites of all time
Pristine:
100 - exclusively limited to things which are incredibly personal, changed my outlook on the artform
To Note:
Thanks to MrSpaceIsCool for the site inspiration, and Nef for rating distribution inspiration