The Rake (revised from The Rake and the Reformer) has two of the best characters I've read: Reggie, who is fighting to recover from alcoholism, and Lady Alys, whose actions show that empathy is a strength. Their internal growth is powerful, and believable, and painful, and wonderful. It has solid history, strong secondary characters who get their own time in the sun, kids, dogs, cats, and horses.
The only reason I gave this 4 stars is some of the plotting. I gave a pass to the setup, which I thought was a stretch but not a painful amount of a stretch. But toward the second half. Reggie finds the single person in the world who (secretly) wishes Alys harm, and it's a person Reggie doesn't like, and Reggie is a closed-off man, but he spills a secret to this character, which fuels an unnecessary suspense subplot. Also, a few of the plot-things turn on Big Misunderstandings. BUT I understand that plot is not paramount in sensual romance, and these characters -- people -- are true and learn wisdom. I will read this again, to sit at the feet of a master of characterization.