As a marketing tool, RP is invaluable - I know someone whose idea of shopping for wine is the cheapest red/white at Costco at or above 90 points. Her palate tells her that it is a fantastic wine and she's happy.

However, as a tool for those with individual palates it's next to useless, apart from the fact that he often ranks good wines low, meaning they are available at a more reasonable price. There are several problems, other than his somewhat unusual taste buds. First, a 50 point scale (for that's what it is - it starts at 50 rather than 0) is ludicrously precise for a matter which is 90% qualitative. Second, the scale ignores the question of what you are enjoying with the wine - is it on its own, with food and what type of food. A wine that tastes fantastic by itself might overwhelm food, which requires a more subtle approach etc. Third, wines develop over time, whereas his score (whilst it can be amended in theory) attaches to the wine, whether the wine improves with age or deteriorates.

Having said all of that, the background information included in his books is invaluable and authoritative, cutting through a lot of the PR BS which emanates from the producers. The best of both worlds is to use him for background info, but use the 4 or 5 star scales favored by for example Decanter, Hugh Johnson et al.