I hope it works better than the dysfunctional Time Left to Read in the Kindle for Android app. It jumps all over the place from page to page and never gets close to being accurate until there are only a few pages left. It is better implemented on my Paperwhite 2, but even on the PW2 it is not very accurate or consistent. I think I bought Moon+ way back when, so I'll install it.

BTW, I think you made the correct decision on skipping the Paperwhite 2 upgrade. After having read a few books now on my Nexus 7.2, whenever I pick up my PW2 it looks like I'm trying to read text through a yellow, fuzzy cloud. Even in a bright room the PW2 sucks compared to the Nexus 7.2. I wish it wasn't too late to return the PW2. Sounds like Amazon shanked the HDX too with the blue border haze. I'm really disappointed in their QC and design process.