There are a few "hands-on" videos on YouTube that are worth a look.
This one I found helpful because it talks, briefly, about the YotaMirror technology. Essentially what this is - if I'm understanding correctly - is a way to run ordinary Android apps, but intercept the display on-the-fly and tweak it so it better suits eInk. He shows this with the Kindle app (about 2:40 on) and it does look like the page-turn animations are less of a problem.
This is key - the ability to play nice with existing 3rd party apps will make it much more attractive proposition.
I have to say, I am slightly tempted. My main caveats, questions are:
- How robust is the back? How will it fare over time?
- Are they planning an update to Lollipop? Kitkat is fine but looking ahead I want my phone to last at least 2 years so it'd be nice to be more current at some point.
- The site mentions wireless charging - I use this for my Nexus 5 and it means placing the phone face up on a charging plate which then gets warm (wireless charging is basically induction). So I assume I'd be placing this eInk screen down? See about re: robustness.
On price? Well it's a pretty decently-spec'ed Android phone with the added feature of the eInk back. On that basis, if you want/need/would benefit from the eInk display then it's probably reasonable. If that's just a novelty for you - or if it's the reason for buying it but the AMOLED screen is surplus to requirements - then it is going to seem expensive.