This is lighter than it looks on the image thanks to the Li-ion battery.
It charges quickly and the power output gives a good 1/2 day of shooting for me in the field. You may get more, as I'm usually using 2-3 lights.
It works well with correctly rated flashes, and with care can be used with higher rated ones; I've used it to power 2x Elinchrom Pro 1000W/s flashes, but you need to set the recycle in the menu to its slowest setting to avoid overloading the unit.
A tip - turn the battery around to transport it so you don't accidentally knock the unit on and discharge it!