I've read the whole Parasol Protectorate series by Gail Carriger and I highly recommend it. I would describe the books as a Victorian comedy of manners with supernatural creatures and romance. They are also laugh-out loud funny. There are definitely steampunk elements, not so much in the first and last book, but pretty strong in the second, third and fourth. It's a quite a mash-up. Alexia Tarabotti, the heroine, is fantastic and hilarious, and her romance with Conall, the alpha werewolf of London, is, hmm, well, hard to describe, but the romantic elements are strong and run throughout the series. As a romance reader, you won't be disappointed, although the romance is not the focus of the books.
As for The Iron Duke, from what I hear, that one is definitely steampunk romance. I've got the book on my TBR pile, but it's a paperback and since I'd rather read on my Kindle, I haven't gotten around to it yet.