yup, heard of it. It's a manual flash so dun expect TTL features like 580EX. and definitely not as much fire power. But if the use of ur flash is just to light up the pictures, it's a good buy considering the built of the flash and the cost
No TTL so you have to set the power level yourself, if you don't mind manually setting the power level and having less power than the 580EX, its definitely a cheaper option
Read that it states that the power level should be as strong as the 580 but test with preproduction unit showed that it was weaker. About the same level as 460II. I cannot find any more test result for the production unit that they are selling now. This is a strobist flash. No TTL. Manual. But strong built. Dedicated buttons for easy adjustments. Can use battery packs! and right, got the ready "beep sound".