more power. even if the light had the same battery capacity but twice the flash power - i would find it VERY useful - particularly for location shoots that often require large and cumbersome strobes. If i could get 50 flashes out of such a device, I'...
i can only vouch for the canon range - i have 600's and the remote trigger which works a treat. the only reason for 3rd party is probably save a few penies but why bother. http://www.johnmckayphotography.com