I just saw a mirasol display device and the question on whether it works well under "low light" conditions is a very legit question. It seems hard to read even under normal office light conditions. The contrast is quite uncomfortable. It gets worse if your turn off the LED front light. Default is half LED brightness which defeats the power saving claims.
All the demos you see show the mirasol under extreme bright light conditions. Believe me, you don't want to read under studio light conditions or bright sunlight. Afterall, why do you wear sunglasses when you go to the beach? Yes, it's too bright.