First off this flash is not for the lighthearted, by that I mean it's on a par with some of the more professional units I've used in the past. Its colour temperature rating is spot on, and at 5500K it is certainly bright. the flash recycle time is about a second quicker than 2.9 seconds quoted by K&F, which can only be a good thing. The flash itself is exceptionally bright and I would heed the warning in the front of the manual. It's more suited to bounce flashing than direct (see the pics from a church). I would not use it as a direct flash on anything other than commercial photography of large subjects, and on a pretty fast flash speed of 1/128+ at around 1/500 sec exposure. Although there is a lambency diffuser supplied I found it a little too thick, but in a near total black shoot It would certainly soften the flash.The slave characteristics are great, no issues coupling with my Nikon D300. I popped outside and placed it at the foot of an Acer in my garden, stepped back 10 meters and set it to 1/64 and the result was none too shabby.The tone or voice prompts are clear and unlike other systems are specific to the needs of the flash, not just generic noises that leave you guessing for hours.Overall the flash is a great piece of kit and whilst its bigger than most, it packs a punch that belies its size and doesn't drain rechargeable batteries rapidly either. It comes with its own case and slips into my camera bag very easily. The hotshoe action is crisp and the pins haven't stuck as yet, which is always good news. 10/10 for ease of use and ergonomics. Another great piece fo kit from K&F Concept.