I prefer Jean-Claude to Richard. Sure, Jean-Claude may be a manipulative, lying, calculating son of a bitch, but he's never pretended to be anything else. He's always been completely open about manipulating Anita, and never attempted a pretense of niceness or morality. In his own twisted way, he's far more honest than Richard, who initially lied about his werewolf status because he thought Anita would have a less than favorable reaction (he was right). Richard maintained an air of moral superiority even after admitting that he engaged in truly reprehensible acts while beta in his pack (which he also witheld from Anita). Jean-Claude may be a bastard, but he's not a hypocrite. He's never been less than completely honest about his occasionally distasteful habits and personality traits. Richard claims that everything he does is out of sheer selfless love, while Jean-Claude admits that Anita does have some powers that are attractive, and her being a necromancer/slayer adds to his prestige. He admits to the political benefits of being her lover/master, and actively--and openly--is on a continuous pilgrimage to claim her body and soul. Richard is saccharinely nice and white-hat, and presented himself as such to Anita--just a good old-fashioned new-age family man, who loves kids, and baking cookies, and old movies, and ripping the still-beating heart out of his enemies to devour whole. Whoops, I guess he forgot to mention that to her, eh? But he's such a nice guy!
Ironically, Anita spouts over and over how much she prizes honesty in a man, and then holds Richard as an exemplar of that honesty. Puh-lease! Richard repeatedly lied to her about his lycanthropy, his past, and his intentions with the pack. He stated over and over how he loathed killing, then went and ate the body of his challenger to the pack. Jean-Claude has maintained a sense of consistency in his character...he's remained the same charming, conniving, manipulative bloodsucker that we were introduced to. Richard did a 180 degree personality change in his fourth book The Killing Dance, showing such inherent untrustworthiness that I can't believe Anita would ever want to see him again. That's the ticket: character consistency. Jean-Claude has it. Richard doesn't. It's that simple.
Also, while it's completely unfair and biased, Jean-Claude's just more interesting. Let's face it: Richard's boring and one-dimensional. He's such a nice guy, so good, so earnest, ho-hum. Jean-Claude has meat, metaphorically speaking. He has depth, motivations besides being the bad guy or wanting to get into Anita's knickers. Richard hides any and all motivation outside of what is considered "nice": pure unadulterated love. In the meantime, he uses her to gain prestige in the pack. Jean-Claude doesn't hide anything. He consents that yeah, he's attracted to her and might love her as much as he's capable, but what's wrong with benefitting from a relationship with her, besides the obvious?
Aside from all of the personality flaws, I have one more reason for my preference: physical stats. I'm sorry, but I just don't get guys like Richard. I've never cared for tall, muscular, tan guys (okay, tall isn't all that bad). It's too much like a classic romance-novel character for my taste...too stereotyped. And Richard's character is stereotyped enough without adding the hunky Fabio image into all of it, right down to the flowing shoulder-length hair. It just makes me picture Miles O'Keefe as Ator of Cave Dwellers fame (watch MST3K, and you'll see what I mean), which is a silly mental image. Jean-Claude, on the other hand...slender, pale, striking dark hair and blue eyes.... A very pretty mental image. :) Also, Richard is too tall...six foot plus strays into romance-novel cliche. Jean-Claude is a more realistic height, considering the time he was born (actually, he would have been very tall in the 1600s...average for men was like 5' 4", women 4' 10"). Yes, I'm getting petty here, but I don't care. :)
The one problem I have here is that Richard is set up as being ideal and flawless, aside from a little extra fur every month, and that's just not possible. Once you set up that flawless ideal, it has to be maintained, which is highly perilous. Flawless also allows no room for growth, character development, weakness, or hell, interest. Trust me, I have been in a relationship (if you can call it that) with someone I thought to be flawless and above reproach. Breaking that illusion is painful and messy, and you lose the trust of the audience, because they feel they have been betrayed. You have set up an impossibly high standard, and then not lived up to the ideal. For all of Richard's pretenses of niceness and humanity, Jean-Claude may be the most human after all.