Do the books reproduce the same kind of chemistry we see on screen?

For me - yes, they have a lot of chemistry though a little different, cause Nikki and Rook are both a little different people than Beckett and Castle. I would say - with less baggage, more independent (Rook doesn't have daughter). Of course romance moves more quickly, especially in the third book it's the big part of the story (ok, I liked it a lot :))). What is the most fun for me - it's all the "meta" you can find there - reading what Castle could write about people he worked with and seeing reflections of many episodes' storylines here and there. Especially if you let yourself believe for a moment that it's actually Castle "fantasizing" about Beckett while writing Nikki. It shows a vision of her (and the relationship Castle would like to have) that I'd say is quite believevable. Criminal plot wasn't interested to me too much in the first and second book, it was much better in the third, probably because the theme was much closer to the main characters. Though - this is where the illusion of Castle being the author of the book is rather thin for me. The plot leans heavily on the finale of the third season of the show and I don't think he would include some of the things in reality. (I still remember it's fiction inside fiction... I talk about it with the friend who like "Castle" and while discussing books I try to repeat from time time : Yes, I know Richard Castle didn't write it. But if he would...:)))
They are really quick and easy for reading books but I think they are quite fun and for "Castle" fans definitely interesting.