I liked Maya in this book. I didn't love her, because she had a few faults, but she was also very kickass. Loved the park they lived in, and all the animals they saved. And I really, really liked Rafe. Just wished Maya had liked him a little more, too ;)
The Gathering left too many things unsolved, but that only makes me want the sequel even more. Can't wait for The Calling :)
You really should read this book, because it is amazing.
Update: Newer and better review of the book can be found here.