The Merry Gentry books are okay; given the sidhe culture that LKH imagines and that the goal is to get Merry pregnant, a certain amount of sex is unavoidable. The plots are stretched thin, though, and as much as I lust after Frost in my heart, the books still aren't her best work. For that matter, the criminal "mystery" part of Cerulean Sins seemed to be just kind of tacked on as an afterthought. Incubus Dreams is supposed to be even longer than Obsidian Butterfly, so we'll see. If she manages to cram that book as full of sex as she did Cerulean Sins, I probably won't read them anymore.
But to anyone who's just starting her series, Guilty Pleasures through Obsidian Butterfly--especially Obsidian Butterfly--are highly recommended. Fast, funny, gruesome, sexy...they have it all.
Morrighan