https://www.mobileread.com/forums/showthread.php?t=79623
I just found this thread going into the pros and cons of this technology.
On hindsight the LCD might be the way to go for annotation due to its speed. However, it is sensitive to lighting angle/quality and viewing angle which makes it less versatile. Given the relative importance of reading is more than writing, the fight might well go to e-ink, but it's dependent on individual reading styles. Personally I like to shift and move a lot, so the viewing angle and glare issue is a major one for me.