It works fine as a reader, its been powered on and off a lot. It gets a lot of use so I never know how many page turns I have done. I have never run out of battery but I generally dont go that long between charges.
As I've said before I generally dont pay that much attention to the battery meter I just charge it often.
I suspect the "purple" (red and blue on together) is the kobo telling me that its pretty close to being charged but isn't quite there yet. I've seen the red on alone and the blue on alone in the past. I generally have pulled it on when its on "purple" as I want to read at that time.