Battery life for my XZU has been pretty good, it has fast performance though I assume the OPO meets or surpasses both of those. The Xperia Z Ultra is more of a tablet that makes calls, while the OPO can go in more pockets. Both are getting 5.1.1 Android, Android M is unknown I think though for the XZU, it's from 2013 after all. I love mine though.
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