There's a thread in the "News" forum about this -
here. The discussion about the newer models starts on page 4 of that thread.
In addition, someone started a thread that lists the specs for the newer models
here.
I have an Aura and last year's Arc that I'm still happy with, so I won't be upgrading. DH is currently using the Glo and is deciding whether he wants to upgrade to the larger Aura. We're also thinking about getting the 10-inch tablet for the family.