Two days of cycling across and back at the top end of the North Island - Day 1 Part 1,Day 1 Part 2, Day 2. Watch was on 100% at the start of day 1. Total uptime of 33hrs, GPS 13:45, external HR, no connection to GCM, battery remaining was 20%.
Possibly another 3 hours or so of GPS so 17 hrs in total maybe. That's not really too far off the specs. Certainly as much as I'll need for anything.
PS
If you're grumpy about battery life, add your complaints to that thread please.:)