I also own the Paperwhite, which I liked but am a serious gadget geek, so when the oasis came out I bought one. I totally understand that it is over priced when compared to other readers, but I have to say I love it! I was sort of hoping when it first arrived that I would feel that it wasn't much of an upgrade. I was wrong, everything about it is better. The form factor is great it is almost a square which makes it easy to hold, with big hands or small, it is also very light so their is no problem with 'hand fatigue' after long reading sessions. The cover acts as a battery pack in addition to the battery that is in the device. What is also nice is the cover actively charges the ebook, so the ebook always has the most topped off charge. The screen is fantastic, better than the paperwhite, which has a pretty good screen already. The charge lasts for weeks and charges fast. It has more than enough storage for your books and wifi downloads and updating is super fast. The leather on the cover gives it a high end feel and is not slippery at all. I also own a Kindle HDX and across all readers I always find myself reaching for the oasis.
I hope this helps, feel free to PM me if you have specific questions.
Good Luck