I am sure that there have been some great improvements in these camera's, but I love my K10D. ISO 100 is amazing and bumping up the ISO gives awesome grain/noise, which I really like. It makes me feel like I'm using film. Yes, the AF is a little slow at times, but I have noticed that it depends on the lens. I'm sure the K-M is a great camera, but having started with the K10D, I think it will be hard to leave 2 dials and weather sealing.
I usually refrain from getting involved in nonsense, but jonnyp's remarks about the Km AF immediately got me to throw the Pentax 50mm prime on my Km and start shooting in my low light kitchen. The AF is extremely fast. I switched from the K10D to the Km to get higher ISO and haven't looked back. The Km beats the K10D hands down.
I think the answer comes down to how you're using the camera. If you're not greatly concerned about high iso, if your style of photography depends less on catching quickly moving objects (in low light), if you want rugged and you like manual controls, then the K10D would be a good choice. It has a better build, two dials, larger viewfinder. I love mine and wouldn't consider trading it for a km. But, you mention AF speed and moving subjects. That sounds more like a job for a kx than a 10D to me. When it comes to visible focal points, my feeling (not everyone's I'm sure) is that if you are doing slow work, centerpoint focus and recompose is often easier than jogging the focal point around and placing the red light (roughly) where you want it, and if you're working fast, you'll be in continuous, letting the camera determine where to focus, and in that case, how much does it matter if a red light flashes? By the time you see it, you're four shots down the road, and there isn't much you can do about it anyway. Now, three points vs eleven is probably something to consider if you shoot continuous on moving subjects. Maybe spring for the kx?
All this said, I use my K10D for all-around photography including plenty of people/event/candid shots, and I only occasionally curse the stuttering AF.
Just remember that auto focus is more lens dependent than it is body dependent. Autofocus is pretty fast on the km (probably slightly faster than on the K20) although as mentioned above, it isn't really customizable. The kit lens focuses fast in good light, but is a little slower in low light.
I don't know that you would be happy with the K10. K20 is much more refined, more accurate metering, better auto focus. I like my K10, but would definitely take the K20 over it for every day shooting.
AF speed depends on both the body and the lens, and K-m has better AWB, AF and metering than K20D. K10D is the most problematic model so far and I would stay far far away from it.
AF speed depends on both the body and the lens, and K-m has better AWB, AF and metering than K20D. K10D is the most problematic model so far and I would stay far far away from it.
+1 on this advice.
The model to go for is the new K-x... speaking as a K-7 owner.