I found a new 501CM last year and it has been a great camera. I usually use an external meter with my other cameras, so this hasn't been an issue for me. If you shoot in rapidly changing light, then get a metered prism. For following a running child, you want a prism anyway. I can't focus and follow action with the waist level finder because the image is reversed. The Acute Matte screen in the 501CM is very nice. I think the 503 has this as well. Manual flash works fine. I even use my Nikon flash in A mode and it works fine since the sensor is on the flash. You just can't adjust the lens aperture without adjusting the flash. And I'm sure it's easier to fool than a TTL setup. I got to hold the camera first, but if that's not possible just make sure you can return it. But I think you really need to live with a camera for a few weeks to know if it's for you anyway.