I like 'em a lot for shooting hand held. They are convenient, and give an improvement in print sharpness over 35mm. In well-lit situations, they are a way to act as if you were shooting small format while getting sharper results. Due to lens speed and minimum hand holdable shutter speeds, I feel that 35mm is superior below a certain level of light. Shooting 220 in my Mamiya M645 feels a lot like shooting 35, especially with the right hand motor grip. They allow the use of fast films with smaller grain than you'd get with 35mm. I most use them when I want to use fast film for whatever reason, but also want less grain than with 35mm. versus square format, I like not having a square and getting more shots on the roll sometimes. The killer tool is the Hassy with a 645 back, as it allows so much versatility, but I don't want to pay for it, or the lifetime of buying expensive stuff for it when the results I get from the Mamiya exceed my criteria already. For a camera of the Hassy style, I use my RZ. I would have a hard time not having the RZ and M645 in exchange for having a Hassy, but maybe I would do it, if it was a nice enough Hassy kit that I got in the end, and for a good enough price......It'd have to be damned cheap, though.