I purchased the K2000, moving from the K10D get ISO 3200 and faster AF. I include some ISO 3200 shots in low light situations with 50 precent cops and noise reduction. My impressions are as follows:
AF is significantly faster in all light situations. Nearly instantaneous in good light.
Feels significantly lighter than the K10D, but once I put on my walkaround work lens, a Tamron 18-250, it didn't make much difference. With a small prime, it was very small and light.
I have not missed the red focus spot as I turned it off in the K10D in anticipation of getting the K2000. In very low light, however, you cannot see the grid and have to center by best guess.
I do miss the two wheels, but having worked with Canons and Nikons at work, I adjusted. Manual mode has an interesting set shutter speed and aperture value operation using the wheel and the ev button. An AvTv mode.
In pictures taken with all modes and even scene modes, the K2000 histogram shows a very elegant perfect curve, low to middle high point to low, without any adjustment.
To my taste, the IQ is equal to or better than the K10D.
There are a lot of adjustments to picture quality, more than the K10D.
Automatic white balance is better, but still needs tweaking.
The pictures below were shot in Av mode, ISO 3200, NR on Weak, Bright picture, center focus and spot metering with the Pentax 50 1.4. Pictures 1, 2 and 3 are in a dark room with a small light. One is the shot without any additional NR, 2 is crop without additional NR, 3 is crop with additional NR in Topaz Adjust. Pictures 4 and 5 are in a completely dark room with only the candle. Four is without additional NR, five is the crop with Topaz Adjust NR.
ISO 3200 with additional NR is pretty much what I expected, more than adequate for newpaper reporting. The K2000 isn't a Nikon D3x, but neither is the price. I am amazed at the functionality you can buy these days for $400.
Hope this was helpful for those thinking about making the switch.
Last edited by tarsus; 12-23-2009 at 06:15 AM.