Battery life is outstanding. Already tested it with my standard internet usage test of a 90 minute Netflix movie with screen and volume at 50%. Location services are on.
Battery testing:
iPad Pro:
A loss of 11% per 90 minutes of Netflix play. Loss of .1222% per minute of use. 7.333% a hour. Total of 12.2 hours of Netflix play. This is with screen and volume set at 50%. Location services are on.
This mirrors my iPad 3 battery life and what I have tested is the gold standard of battery life for a tablet.
This is very impressive considering it's driving 4 speakers sounds louder than all the other tablets and it's brightness is brighter than all the other tablets set at 50% brightness. In the real world, I would set it to 40ish % and volume lower and get considerably better battery life.
To put this into perspective here are a few other tablets and how they performed in the similar test.
Samsung Tab S 10": loss of 23% per 90 minutes giving it a 6.52 hour Netflix play time.
Lenovo Tab 2 A10: loss of 17% per 90 minutes giving it a 8.82 hour Netflix play time.
IPad 3: loss of 11% per 90 minutes giving it a 12.2 hour of Netflix play time.