This is a really nice mid-gen refresh, IMO. It drives the entry point prices down (when was the last time you saw THAT in tech?) and it makes some really nice improvements to the newer SKUs.
I don't think it's a must-buy if you already own one, but if I was still using a Deck as a daily driver I would certainly consider it. The idea of a 10 hour battery on a handheld PC is super appealing for me, considering how often I'm playing stuff at 5W.