Larger Screen: Since the original Kindle in 2007, Kindle screens have been six inches (except for one large format device). The new Kindle Oasis has a 7 inch screen, which is supposed to have 30% more text than a 6 inch screen.
Waterproof: I have been waiting for a waterproof kindle for a while. In 2009 I picked up a waterproof case and loved it. It was floating and I took my kindle in the ocean to read. It was my dream vacation activity. Eventually the case broke and I upgraded to a new kindle. In 2015, I picked up a WaterFi Kindle, which was an after market Paperwhite that added $100 to the price of the Paperwhite and nearly 50% additional weight. This Oasis is now waterproof, a boon to bathtub and beach readers everywhere. (IPX2, which is 2 meters of water for 60 minutes.)
More Storage for Audiobooks: The Oasis has either 8GB or 32GB of storage for books. A 32GB Paperwhite has been available in Japan for a while because of their focus on Magna comics. So this isn’t a surprise. What I was surprised about was that the storage is also for Audiobooks from Audible. There is not a speaker on the Oasis, but there is a bluetooth connection for either a Bluetooth speaker or headphones. This I would use.