Well, it works.
I have just given the new Nissin i40 flash a run with the little Fujifilm X-10 that takes the editorial photos for our shop - and i am impressed. Impressed enough to fork out some of my own money for one.
It slotted onto the hot shoe and went into TTL mode flawlessly - no big surprises there. Tilt, auto zoom, all the bells and whistles we expect from modern flashes.
Then I turned it to Manual and shot the sequence of flashes you see in the photos. 1/128, 1/16. and 1/1. But you see how it worked? - no cord connection - the flash operates as a slave from the X-10's little weeny on-board flash.
So, you can hold it in your hand, shoot your main from the end of your arm, and have the little on-board peeper as a fill. Or put it on the shoe, dial it up to 1/1 and do fill flash out in full sunlight. With the X-10, 20, 30 or X-100 series cameras you can synch up to at least 1?100 - I tried it. Woo Hoo.
It's got a video light there, and an auto setting for non-TTL cameras...and a metal shoe for reliability.
And if you are a micro 4/3 person, there is a version of this for your camera. Also if you are a Canon or Nikon person.
$ 295 looks like a real bargain for this much Kerboom.