JonnyT I have the BigMe Highbreak Pro. As for flicker, it's great when not using the backlight. I use it with natural lighting and interior lighting. The backlight (which may be DC dimming) doesn't agree with my eyes. I never thought this would be an issue at all, but I don't seem to be the only one who thinks this.
That said, the phone doesn't continue to refresh once the screen has loaded unless you have dynamic content like a video or animations playing. That's the beauty of E-Ink. It's also black and white, so there are compromises.