Summary: I have a been a Pentax SLR owner for 30 years and so have acquired a collection of lenses, all of which work on my K5 DLSR thanks to Pentax's excellent K mount. After thinking about it for nearly a year I finally purchased the 200mm f2.8 and I have to say after two weeks, that this is the first Pentax lens I own which consistently surprises me with the "snap", colour and life it brings to every shot.
Summary: I've gone sort of nuts buying Pentax lenses for my k5 and kx. I have the 10-17 Fisheye, 15mm Limited, 21mm Limited, 35 mm Macro Limited, 40 mm Limited, 70 mm Limited, 200mm DA*, 50mm Takumar m42 and just bought the 50mm f1.2 SMCA. I take a lot of events/street, flowers and nature shots. I don't use this lens a lot partly because I don't need a long lens often. This is a big lens with a lot of glass. It's an amazing work of art to hold.
Summary: Lens was received quickly and well packed. Photo Clarity is very good, The F2.8 allows for shooting at low light levels and works well with the Pentax K20D body. Auto Focus is quick and smooth but a little soft in some situations. Ruggedness is very good for a lens of this price and I'm not afraid to take it out on days with a light rainfall. It has become the lens I use the most with my SLR. It's an excellent lens for the price.
Summary: I bought this lens to shoot bike races and the like, figuring its length and f/2.8 were just right. I've been disappointed with it producing purple fringing on high contrast edges even in the center of the frame, worst shooting wide open as one would like to do for action sports. It's not the normal edge CA that can be mitigated in ACR or ALR; it has a small amount of normal CA.
Summary: The "Star" version lenses are very finely crafted tools. All fitting are tight and movements are silky smooth. The "IF" focusing is incredibly fast and quiet. While the lens is a handful, it is not unreasonable to hand hold. I was at first uneasy about not having a tripod collar (as the 300mm has) but the 200mm is well balanced and can easily be supported by hand for your typical one hour sports event.
Summary: Arrived promptly, in perfect condition. Haven't had a chance to use it much but feels nice on my K7. Love the f2.8 aperture, some huge glass to capture light so lookng forward to taking good shots. Focus seems fast and good too. Construction looks and feels very good.