I really like to use Qflash in outdoor sports photography. It gives me this really good quality of light and the ability to work in any weather condition.
I carry two Qflash T2 and two Turbo Z Batteries. They are light enough to let me ski or bike with them in any environment and they have been solid enough to endure this lifestyle.
I am really happy with their performance and reliability, especially for location lighting, like the cold-snowy-wet weather of this picture.