Amazon.co.uk (and probably likewise with .com) publishes a list of the Top 1000 reviewers.
The number one reviewer is Jason Parkes. He's written 709 reviews. Some people have written even more, but look how lengthy all of Jason's review are
From a very quick look it looks like Jason's reviews are almost always 5 out of 5 stars. Maybe that has something to do with why he's at the top of the list.
Makes you think... How much time do these guys have on their hands?