How seriously should users take supposedly independent reviews of software products?

This is a thorny, yet important, question for users, especially as they try to make decisions about upgrades, new products, or even about switching products.

Product reviews are comforting to users when the reviews reinforce initial impressions. They are marketing tools for software companies and re-sellers, who re-print favorable reviews, and ignore unfavorable ones. But if they aren't credible, favorable reviews can lead users down a dangerous path, toward making poor choices.