I can't remember which one. The earlier ones. I'd order from the Damien Lovegrove shop as they sometimes offer deals with their videos.
It's a manual only, and you can adjust the power from the trigger on top.
HSS sounds good, but in reality I'm happy to use a 4 stop neutral density filter.
With my style of photography, I never try and over power the sun anyway.
In general, if I'm using flash outside I tend to stick with my Nikon stuff. But indoors and for quick shoots, I use the cactus.
At the moment I'm using the cactus to trigger an elichrom studio head as fill/main light.
I've also used my Nikon on optical slave to create a two light set up.
It's smaller than my Nikon stuff and cheaper, so if it falls over, I won't be so heart broken.
I'd recommend it. Mandy