Are Review Units Better Than Store Versions?

Anonymous Howard writes "Every now and then you hear about hardware manufacturers optimizing their hardware for certain tests or games to make their hardware look superior. I was surprised to hear of a new controversy brewing over reviewer units sent to hardware reviewers. This article claims that Samsung is sending LCD monitors with a contrast ratio of 700:1 when the consumer version of the same monitor has a contrast ratio of 450:1. Various sites list different specs for the same model, so it's somewhat confusing to know for sure which is correct. I don't doubt this happens, but I'm surprised that it would be this blatant. Has anyone heard of other stories of manufacturers being deceptive so that they could get better reviews?"