Some users are complaining about the increased size of the updated app which weighs in at 13.26MB compared to the 2.51MB size of Google Books. Also,there were some complaints that the Send-to-Kindle feature was turning small sized documents into behemoths. One user said that a 3MB PDF file grew to 33MB. But for the most part, users seemed to be pleased with the update. The app puts over 1 million books at your fingertips.
source: GooglePlayStore via AndroidCentral