I don't think that you determine crazy by stacking odd comments up next to eachother (also what are we comparing? The rate? The number? O'Reilly has been on the air longer, so do you have to provide 6.5 comments for every 1 Olbermann makes? What is a crazy comment?).
You determine anchored in reality by whether their worldview appears to be the creation of a rational thought process, as determined by how they present it. Olbermann, O'Reilly, and Beck all more frequently than not espouse things that are generally supportable (yes, I've read their books, really) if not necessarily things I agree with, but their thought process is based on idealism and preconceived, unchallenged notions rather than rational logic. Thus they seemingly wander from sane to insane, often in inside of a minute, simply because the reasoning process itself is flawed.
Now if you're asking me which is better, I think O'Reilly and Beck are generally supporting an unscientific, anti-reason cause that is based on 14th century theology, paranoid thinking, and a large dosage of PNAC's imperialistic ideals, and thus frequently appear nuttier, because they're supporting a cause that is in general nuttier. While Olbermann is frequently supporting a cause that is at its core rational, if its fringes wander weird places.
But I shant be surprised when O'Reilly comes out against the anti-vaxxers or Olbermann starts promoting homeopathy or something, because I don't base my thoughts on these people on stereotypes.