Yesterday I went to Seattle to visit some of my family. My aunt has the new Kindle Paperwhite (not the one @Slacor had) so I decided to try it out. The verdict? It's good
Tested for 10 minutes in a "good" environment, no eyestrain. (No PWM detected from "reading light" but even on minimum brightness the backlight stays partially on. I noticed in standby with the ads the backlight stays completely off so it may be possible to modify the software to add a backlight on/off function. So I think I may be getting the new Paperwhite for myself soon.
Also my cousin had the new Moto X (don't know which model but it was running lollipop ) and despite being an AMOLED based screen I was unable to detect PWM with hand waving test as well. Something to look into perhaps?