Bolick gives a more nuanced view that actually addresses more of Rehnquist's work on the court (though less than I would have expected), while Dershowitz emphasizes evidence of Rehnquist's personal character which mostly derives from before he was on the Supreme Court. I was surprised that Bolick didn't mention some of the recent cases (such as Raich v. Ashcroft and Kelo v. New London) where Rehnquist voted for liberty (and was unfortunately in the minority).
Yet I have no doubt that there is accuracy in both descriptions. Bolick has in the past seen people as defenders of liberty who have done much to destroy it, such as former Attorney General John Ashcroft. Dershowitz alternatively takes courageous stands in defense of liberty and crazy stands which oppose it.
One area where I was less than impressed with Rehnquist was on religious liberty, specifically for nonbelievers. He (like the majority) went the wrong way on Elk Grove v. Newdow (the Pledge of Allegiance "under God" case) and (unlike the majority) the wrong way on the McCreary County v. ACLU case (Ten Commandments display in a Kentucky courtroom which included a written statement that the display was "in remembrance and honor of Jesus Christ, the Prince of Ethics").