First impressions, it does what it says it does! And I would definitely buy again if needed.
Battery life I haven't fully tested, didn't fully charge it prior to usage.
It seemed to drop about 30% with about 35 minutes of use set at about 50% pressure at the shower head. (Lower showerhead pressure will cause more resistance on the pump and more than likely cause higher battery usage.)
There's a pressure dial on the shower head, I timed flowrates at highest and lowest pressure setting.
Lowest pressure setting flowed about 1 gallon in 2 mins.
Highest pressure setting was about 1 gallon in 45 seconds.
Took around 15 min shower with intermittent water usage, (the pressure control also can be pushed in to completely cut off water), turning off water to shampoo/condition hair along with scrubbing body.
This was at about 40-50% water pressure and used about 6 gallons of water.
All in all its a good product!