Complaints are valid
The complaints people have made here about Google Play Books are correct. Highlighting is painful, the app becomes almost unusable when out of wifi range (I mean for just reading, not downloading), and it tends to be quirky and unreliable. This is a shame, because there is a lot to like about the Google Books concept (it works a lot better on a Mac through Safari). I hope they get it right.
dgsb about
Google Play Books - Books & Comics