Crowning Glory -- The Saga Continues is a sequel, the first few chapters provide an in-depth recap of the first Crowning Glory story, ensuring that new reads can enjoy it as a standalone read (although I would heartily recommend reading both).
With the addition of Tawni Katherine Bonds as co-author, Carollyn Olson tells a story here that is darker and deeper than the first. That is not to say it is a sad story, but it does deal with some dark themes and sad memories. It is a difficult read at times, especially with Ryan's memories of bullying and abuse, his self-hatred as a freak, and his drunken assault on Erin (Aaron), but it is a stronger story for confronting the reality of so many transgender experiences.
Having said that, there is still a lot of fantasy and fun to the tale, with a new transformation from macho man to stunning beauty. There is an even stronger theme of forced (or, rather, encouraged) feminization behind the story, but it is nicely countered with scenes of confession and therapy. Ryan was hardly a likeable character in the first book, and he becomes thoroughly detestable early on here, but Carollyn & Tawni develop him wonderfully, transforming him into a likeable, sympathetic character before the end.
Whereas Crowning Glory started with the happily-ever-after, before rewinding to demonstrate Aaron/Erin’s re-emergence, Crowning Glory -- The Saga Continues is a more linear tale, and one that keeps us in suspense as to how Ryan/Kat will develop and where that journey will lead.