I recently had the chance to thoroughly test one of these out. And lets face it folks, when you are thinking of purchasing a lens like this, you are purchasing it for the 400mm. The zooming ability down to 200 is just a bonus to make it easier to frame.
With that said, through my tests, I could not get the lens to shake CA at 400mm. Anytime a bright spot met a dark spot, the bright spot would plume with purple fringing. I was shooting a sign against a building about 400 feet away, and I tried every f-stop the lens had. F-11 provided the best results with about 3 pixels worth of CA. This may not sound all that bad, but f-11 is SLOW and CA at that f-stop is unacceptable. Plus the purple halo's give photos a terrible "cartoon" quality, even at f-11. At wide open, forget about any signs of quality. The CA was visible on my D200's review screen without zooming in (which is when I first noticed it)!
I never got around to testing the lens at less than 400mm because at that point I decided to pass (my Tamron 1.4x converter + any of my 200mm+ lenses (Nikkor 18-200VR or Sigma 28-300) provided better photos than this did without the converter). Results might be acceptable with film, I wouldnt know. But on my D200 it provided me with disappointing results and I'm glad I was given the opportunity to test shoot the lens before purchase, otherwise I would have ended up with this sub-standard lens.