Originally Posted by ftpaddict 
I've played around with both.
The answer, in short, is
yes. Noticeably better.
I assume you mean the K20D is better than the k200D, not the other way around.
I've owned both the k200D and *istDS (which has the same viewfidner as the K20D). I'd say I can see the difference when comparing back to back. But the K200D is still good enough in practice most of the time, and installing the OME53 magnifying eyepiece helps a lot in the cases where you might wish the K200D viewfinder was bigger.