Ignore price for a moment. Depending on your mindset high price might either mean too expensive or mean premium product. Pretend the Voyage and the Oasis were the same price. Ignore the 'missing' features (TTS, waterproof, screen size, etc.). Which would you rather own?
Voyage: Narrower, taller, heavier. Not easy to pop in and out of the case so you will probably be using it with case on. Origami case lets you prop it up. Battery is sufficient for most needs.
Oasis: Lighter, shorter, wider. Naked: more ergonomic but battery is limiting. Easy to add/remove case so probably will use it naked at home and put in the case for extended reading and on-the-go use (if you can find where you left the case last
). Increased led lights.
Which is better?