I've browsed through both of them in the local bookstore. My suggestion would be: if you're interested in the subject matter (the Battle of Trafalgar and the frigate actions of the War of 1812) and don't already have several books about it, these books would make a good, sound, reasonably-priced start. If you do have some books about the subjects already, these two probably won't tell you much that you don't already know.
I was hoping for reproductions of some contemporary plans, or even paintings, of the Redoubtable. No such luck. (I have the impression that, though French 74-gun-ships of the period in general are pretty well documented, not much in the way of specifics is known about this one.) Both books rely heavily on modern, commissioned paintings - nice (certainly better than I could do), but they don't add much, if anything, to what's available in other sources. On the other hand, the text looked solid and reliable.
I gave both of them a pass. But I wouldn't try to talk anybody who's relatively new to the subject matter from buying them.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.