Same here - not a Nora Roberts fan, but LOVE the JD Robb series. I even broke down and started getting the hardbacks* when they switched formats on me.
I don't really get "overdone" from them at all, guess it's a matter of preference? Or just that I've read all 20+ of them, and don't remember the earlier books as clearly, lol. I have that problem all the time when introducing new people to series I love - I forget that of course the first book would be the weakest in the series, as it was written much earlier and a lot has happened (to the writer AND characters) since then.
*I HATE it when they switch format mid-way through a series, because that means I either have to wait 6 months to a year longer for the book in paperback, or I have to pay twice the price to get my "fix". And if I wait, I either risk being spoiled on the plot all that time, or I have to avoid all my fan sites and message boards relating even remotely to that series. Grr...