Best at Analyzing Comps: A Realtor, Investor, or Appraiser?

[Jason Grote]

I am curious as to what fellow investors think about who is the most qualified to analyze comparable sales. I understand that Realtors and Appraisers are the ones with legitimate access to the MLS, but if you had to pick between a Realtor, an investor, or an appraiser, which do you think will hit closest to the mark for an investment property that you are analyzing? This is assuming all are equally seasoned and experienced.