I've had the turbo power pack on my phone for a couple days.
It makes the Z2 Play about the size and weight of the Moto X Pure Edition. Maybe a bit heavier.
I have it on efficiency mode, which does nothing, until the phone is down to 80%, then the pack keeps the phone at 80%.
I haven't charged either all day and they've been off the charger for 15.5 hours. Today was moderate use, with much of the day spent in a low signal area. The pack is at 2% and the phone is at 80%.
I am using the Verizon bumper with the Turbo Pack. The bumper is obscuring the charging port on the Turbo Pack. Last night, the phone was at 80%,while the Turbo Pack was dead. The Verizon bumper allows easy removal of the mod, without removing the bumper. I popped the mod free from the phone and charged the pack and not the phone. This morning the pack was 100%, while the phone was about 76%.
I don't think I'll use this setup daily, because I am not away from charging sources and the bulk /weight is a bit much.
I really like the slim and light Z2 Play.
Also, I am unsure why my pics are doubled. They aren't when I choose to edit the post. \_0_/