I received my K-01 last night - black model (which is actually two tone black and silver.)
I had pulled the trigger for essentially pragmatic reasons. The K-01 seemed a very reasonably priced backup for the K-5, fulfilling the promise of video done right (which the K-5 never achieved.) I liked the look of the K-01, as I enjoy minimalist modern design. (See Dwell magazine.) But I was a little leery. The few glimpses of a K-01 that I have had, it looked LARGE, especially when surrounded by m-4/3s cameras.
When I took my K-01 out of the box last night, my whole attitude changed. Wow. In the hand, this is a handsome camera. There is a sense of proportion to the camera which is very balanced. The size and width fit perfectly in my hand, avoiding the awkward "pinch" style holding that I resort to with smaller cameras. The fit and finish of the camera are astounding. I have the K-5, MZ-S and LX, so I am familiar with Pentax's ability to make a high quality device. Contrary to my expectations, the K-01 is equal to any of those previous devices. Different, yes. It's clearly meant for a different way of shooting, really for a different generation of photographer. I hope that younger generation will look past the K-01 being bigger than the competition and handle the camera, considering it for its own merits. They will be pleased.
The best word for the cameras quality is SOLID. No flex, cool metal to the touch. Sturdy metal knobs with good feedback. Buttons that feel better than those on the K-5. The video update rate on the viewfinder/screen is very fast and fluid, and the image is clear bright and accurate. Autofocus is much better on the K-01 than on the K-5 Live View. I haven't updated the firmware, but I understand AF gets even faster which is great. But the best part of the camera, from a tactile point of view, is the shutter. The sound and feel of the focal plane shutter firing, without any sound of mirror flipping or film advancing, is the most reassuring SNICK. It leaves you with no doubt that the camera contains a real focal-plane shutter. There is no point-and-shoot fake-camera-sound-effect. After the snick, the image immediately pops up on the screen for review. The upgraded PRIME is obvious - the K-5 seemed speedy but the K-01 is fluid and so fast I never notice that the camera is thinking. Everything happens instantly, or at least faster than I can think and press buttons.
I mounted my FA 43 on the camera, which seems the perfect match, and happily spent an hour lost in the tactile joy of picture taking with this machine. At the end of the hour, I flipped the camera over and noticed Marc Newson's signature for the first time. I smiled. You earned the right to sign this camera Marc. Thanks.