I just finished Joseph Ellis' 440-page biography of Thomas Jefferson, American Sphinx. Ellis is very readable, and there is always a good-natured tone to his prose. He is very frank about the inconsistencies and idiosyncrasies of his subject, another iconic figure like His Excellency, George Washington. Certainly there is no shortage of contradictions to observe, and Jefferson ultimately never even recognized most of them.
A friend who got his PhD from the University of Virginia had the experience of Jefferson that Ellis, growing up in Alexandria, did of Washington -- he was simply a natural force, ubiquitous in the environment. My friend, not a fan of Jefferson anyway, didn't care for American Sphinx, and I can see some oddities about the book that may have bothered him. Ellis jumps around a bit when you compare his chapter headings with the actual text, such as quite consciously dating the chapter dealing with Jefferson's second term after he retired to Monticello. The best I can say is ignore the headings. There is practically nothing about Jefferson prior to the Continental Congress, which Ellis probably did because many of the contemporaneous sources were lost in a fire at Jefferson's Shadwell property. The new information which came out in the DNA study linking Jefferson with Sally Hemings is awkwardly appended to the original appendix, though the introduction to the paperback revised edition does warn the reader at the start (relevant material is inserted smoothly into the main text).
All in all, though, I found it a useful book. The major observations highlighted are Jefferson's tendency to think in moral dichotomies, not at all nuanced like the modern liberals we associate with him. In fact, as Ellis points out from his perspective in the mid-1990s, the conservative wing of the GOP is most like Jefferson in its ingrained suspicion of expansive government power (a suspicion sunk beneath the surface in the present administration). Jefferson's command of written language was probably unmatched in his time (as Chernow noted, Alexander Hamilton, while brilliant in thought, was often prolix on paper), but he indulged himself from the very beginning with fantasies of societies running smoothly without government at all, once people were freed from the weight of residual feudalism and monarchies (he included Adams's and Hamilton's version of Federalism in the latter vein). Any realities which intruded on his philosophical reflections were simply denied a place in thought; the existence of slavery in his home life, for example, was made as invisible as possible. In fact, while Jefferson was documentably duplicitous, treacherous even, toward his political opponents, he seemed to truly expert in self-deception more than any thing else.
Overall, I admire his language skills and the nobility of many of his expressions, but I have a mixed pity and dislike for the character of the man. I have to agree with the sentiment attributed to David McCullough, who supposedly started to write a dual biography of Jefferson and John Adams, and grew so tired of the backbiting Sage of Monticello that he relegated him to be a supporting character in the Pulitzer-winning biography, John Adams, that was finally written. American Sphinx is a useful book for understanding why that would be.