Good thread. For me, these albums are on par. NI may be better as an overall album, but my favourites on UG are more meaningful. I actually believe the best songs from each could have been combined to make a beautiful record up there with the classics.
In terms of quintessential Tori, that's hard to define but I think the below are mine.
Unrepentant Geraldine's
America
Selkie
Oysters
Forest of Glass
Native Invader
Reindeer King
Cloud Riders
Wildwood
Bats