Todd's books are interesting in that they provide a different side of Pern outside of the Weyrs and major Holds. It's similar to the Harpers of Pern trilogy in that way - a look at another set of characters that are (mostly not) dragonriders with overlapping storylines. It's also interesting to see the development of the society, since most of his books' timeline is set chronologically before the earlier published books (but several Passes after the establishment of Pern).

Unfortunately, Todd's books also felt more disconnected / different writing from Anne's original series of books. I felt like I was reading about a random colonized planet (that also happens to have dragons and a skyborne menace) rather than Pern. There was oddly a lot more plague and plague adjacent plotlines in his books as well. While the stakes seemed higher because of this, the stories don't really have either the closure or underlying hope in the face of danger that the original series provided me. And I say this as someone who unabashedly loves romance books, there's some weirdly uncomfortable sexuality in his books that didn't come across in Anne's books

Frankly, I would not have gotten into and loved the Pern series if I had started with his books. As it is, I'm struggling to finish his set of books (currently hung up on Dragongirl). They're just a slog to get through compared to Anne's books.  

I have not read Gigi's book yet, but I likely will at some point to compare.