Before I go on, let me say that I am a fan of what the Michelin guide has done in the US. Unlike Michelin's stodgy preferences in France for stifling traditional establishments, Michelin inspectors in the US have more often rewarded casual restaurants with good food. It's easy to point out ratings we disagree with, but I pored over the Michelin books for San Francisco and believe they are overall the best guides to dining in the area.
However, once issued, these ratings may have an adverse effect on the restaurants included if you care more about food than decor.
Here's a quote from the abstract of the paper by Olivier Gergaud, Karl Storchmann and Vincenzo Verardi:
While we do not find any Michelin-induced increase in perceived food quality, we find strong Michelin effects on service and decor quality ... Michelin-reviewed restaurants enjoy substantial returns only to service and decor improvement. Our result suggests that (Michelin's) opinion on the New York City restaurant market exerts a negative externality on gourmets by giving restaurants incentive to invest mainly in service and decor leading to higher prices.