I have a 1000s and a Pro TL. I bought the Pro for the interchangable backs. There's a couple of features on the 1000s that I like that aren't on the Pro, the DOF lever ( youmust use the lense Auto to Manual switch to achieve this on the Pro) and the second shutter release on the 1000s is much nicer to use when holding the camera in portrait mode. I have a power drive for the Pro and really only use it when taking pics of my boys in a semi-studio (the kitchen!) setup. Out in the wild, I'm happy to crank. The 1000s takes a std cable release (nice) but the Pro needs some electronic gismo (which I don't have). Regarding the interchangable backs... because you only get 15exps on a roll of 120, it's not a huge problem unless you regularly want to shoot the same scene in multiple films. It's come in handy a few times but for the couple of years I only had the 1000s I managed to get around it, but I hardly wanted to do this anyway.