Originally Posted by offertonhatter 
I would say that due to the reduced zoom range of the 55-300 over the 18-250, and possibly better optics, it commands a premium price. the 18-250 is in essence a tamron lens with pentax coatings, but the 55-300 seems to be a Pentax own model. It will be interesting to see how it compares with the Sigma 70-300 and the Sigma 70-300 APO lens which are very reasonably priced. It will be interesting.
The 55-300 is sure interesting and might be a way to extend upward in length, since I can't really motivate buying the much more expensive DA*300.
What about the FAJ 75-300? It is still for sale new here for a low price. What I heard it is better than the different FA/F 100-300 versions. How do you think it might compare to the DA55-300. The only possible advantage I can see, besides the price is that it is full frame, but without an aperture ring I'm not likely to use it on my film cameras and I might never go FF even if Pentax comes out with a FF camera, all depending on future prices and where the whole market goes. But forgetting that for the moment, just comparing FAJ 75-300 with DA55-300, what are the likely differences that would motivate me to go for the more expensive 55-300 (more than twice the price)? And are the Sigma/Tamron offerings so much better that I shouldn't think about the FAJ anyway?