Review on YONGNUO YN660 Speedlite: Versatile Wireless Manual Flash with GN66 Power for Canon Nikon Pentax Olympus by Ashley Lynn

Very glad I tested this before photographing property. After about 25 flashes using the Yongnuo 603 wireless triggers (which work well so far) this flash decided to stop on every shutter, even after every 5th flash cooling session. Care must be taken not to overheat the flash too much, but for the Yn660 this slight burn-in was too severe. The batteries were hot after 10 non-consecutive shots at 1/32 by the way. Not good. Tried using the flash on camera to make sure it wasn't a trigger system, same result. 1 flash if you're lucky, out of every 10-20 triggers. I really wish it would work for the price but as they say too good to be true. Coming back to the expensive but reliable Cactus or Canon models.