Michael Gertenberg is one of the few analysts who doesn't say it's all in their heads and doesn't make ridiculous predictions about Apple. He worked for the research group Gartner, with whom Apple has collaborated several times in the past, using their market charts in its keynotes.
Having spent most of his career covering Apple and other tech companies, Gartenberg has decided to pick a camp. He has reportedly accepted a job on Apple's marketing team, reporting to Phil Schiller.
In addition to being an analyst at Gartner, Gartenberg has written several articles for major technology sites, and has also said some smart things about Apple.
However, in the past he had worked for a short time at Microsoft, but apparently he didn't like it there very much.
Dimitrios Georgoulas @ GreekAppleNews

