If you haven't met him already, you can get a fairly good idea
from Mike Tomasky's book review. Tomasky writes about how McCain became "the maverick" rather than "the flip-flopper", and how he still is viewed as the "straight-talker" when he has pretty much relinquished all his old values and replaced them from the stock of the ueber-right.
As an example, only ten years ago McCain expressed support for Roe v. Wade. Now he is opposed to abortion even in the case of rape or incest. Or so Tomasky tells us.