Ultimately, it seems that the first book was just a teaser of things to come. I think that that book still excels the best at all three of these at being a soft, fluffy slice of life story about a man and his wife trying to live their best lives, but where A New Era is comparatively lacking in Johnathen/Thyra interactions it more than makes up for in the numerous other characters that now inhabit this world, and the story that it's setting up. In other words, it's strengths are somewhat different from the original, but it's overall a better and more complete experience.
The new characters only introduced at the end of The Gryphon Generation really come into their own here. Aadhya has become one of my favorite gryphon characters period, and Rachel is absolutely adorable. Antonio is a great and suave wingman, but I feel he doesn't really get his time in the spotlight until book 3. Still, though, he's a welcome presence. Isabell is still one of my favorite characters, and we get some unexpected bonding time between her and Johnathen while she's in the hospital and Thyra is away. And of course, Thyra herself is an absolutely wonderful protagonist, who is relatable, complex and compelling in the choices she has to make and the mix of plot-centric conflicts and more every day worries that she has to deal with. Just because she's a gryphon doesn't mean she isn't the most interesting and well-rounded person in the series. She may just be my favorite gryphon character of all time at this point (though my gryphon book experience is sorely lacking).
The villain side of things is a little bit more underwhelming. Alexander Bizzell clearly grows as a writer here but there are still some growing pains. I think what Bishop Matthew represents is a compelling conflict, but he himself is just a bit too much of a mustache-twirling villain for me to get super into. That being said, he truly goes unhinged in this one, makes way for an endgame villain that is, without too many spoilers, significantly better and ties directly into Thyra's past and her main struggles. So it's not all bad here.
The thing I like most about this one is the Gryphball! I'm not much of a sports person but it's entirely different in fiction and especially with gryphons. Alex really knows how to amp up the personal drama and stakes in the game and create a thrilling and fun experience, and each gryphball scene was a new highlight of the story.
Overall this was a really strong step forward for the series that really fleshed out the world and characters and told a much more complete story than the original. I still like the original for it's really romantic slice of life elements, but this is definitely the better of the two overall.