what's better gregory's novel about mary boleyn or about catherine of arragon?

I've read all her books except the most recent one and I found both of the books you mentioned to be fascinating--enough I didn't want to be interrupted while reading them. Each one is about a completely different character in the same setting (Tudor times) but with different purposes. Mary was a part-time mistress, for lack of a better word, and Katherine was his first wife. Mary would have pushed Katherine off the throne if Henry hadn't seen Anne who proved to be a better, more skillful lover than Mary. In the book about Mary there's more information about the Boleyn family's manipulations and it's more titillating. That's probably due to the fact that the girls were young while The Constant Princess tells her life story.

My opinion only: the only books of hers I didn't care for were the Wildacre trilogy. I'm not a prude, but the subject matter got to me after awhile. The final book in that set was just plain boring.

The Constant Princess, about Catherine of Aragon

what is Gregory's latest novel