You say you like to take people pictures, but how? Street photography, posed, studio? Bear in mind that using a MF camera with a waist level finder means just that, you'll be shooting from the vantage point of your stomach, about the viewpoint of about an 8 year old child. This would probably be most noticeable if you were fairly close to a standing subject, but still it's a different perspective than eye level. If you don't enlarge more than 11x14, your probably not going to notice the difference between 6x7 and 645. The 645 is a much easier camera to handle. I've used all medium formats and found that to me the Pentax or Mamiya 645s with eye level prisms are the easiest to use if your out and about. The basic Pentax has the advantage of multiple exposure choices including my favorite, aperture priority, and a built in motor drive. I also like the old Rolleiflex and Rolleicord cameras, as they are light and have decent lenses. (the newer ones have better lenses) The RB67 and RZ67s are great cameras, but are heavy and somewhat awkward to use hand held. If money is no object buy a Hasselblad. It'll last forever, and give as sharp a picture as you can take. If money is a real issue, buy a Holga, and just have fun taking weird pictures. There are lots of options for you to choose from, and you will definitely see the difference from 35mm with almost all of them. (except maybe the Holga) Good luck, and try to enjoy the process.