Now first off, I am 99% not a flash-using photographer, but I have used them in the Nikon system a bit. Never with my K-7. I'm looking at getting one for pro work (primarily reportage, not studio etc), which really means the swivel head is a must, as well as wireless. What I'm really wondering about is the quality to price of the AF-540. Would I miss much going to Metz or Sigma? Would you consider it the best option for a Pentax DSLR? (with mostly Sigma lenses). I have also read up a bit here: http://pttl.mattdm.org/ Thanks for thoughts.