works amazingly well, i use one in my gameboy for file transfers (retro-pie)
Connects quickly, and has low power consumption, while transfering a large file, i measured it with my fluke, at 95-150mA, which had me blown away at how low that was. My other wifi adapters for example, run at closer to 500mA for slower speeds
My RPi needs a fan, heat will leech into the battery, so people saying I don't need a fan, don't understand how Li-Po batteries are affected by high temps. Cool pi = cool battery.
I would very much so like to see a Pi2/Pi3 Zero, power and size.