Wine Spectator's 100-Point Scale
95-100 Classic:   a great wine
90-94 Outstanding:  wine of superior character and style
85-89 Very good: a wine with special qualities
80-84 Good: a solid, well-made wine
75-79 Mediocre: a drinkable wine that may have minor flaws
50-74:  Not recommended

The Wine Advocate Rating System
96-100:   An extraordinary wine of profound and complex character displaying all the attributes expected of a classic wine of its variety. Wines of this caliber are worth a special effort to find, purchase, and consume.
90 - 95:  An outstanding wine of exceptional complexity and character. In short, these are terrific wines.
80 - 89: A barely above average to very good wine displaying various degrees of finesse and flavor as well as character with no noticeable flaws.
70 - 79: An average wine with little distinction except that it is a soundly made. In essence, a straightforward, innocuous wine.
60 - 69: Mediocre: A below average wine containing noticeable deficiencies, such as excessive acidity and/or tannin, an absence of flavor, or possibly dirty aromas or flavors.
50 - 59:  A wine deemed to be unacceptable.