What you can get from 120 film really depends on the camera.
I can get very decent negatives with my 6x4.5 Bronica ETR system, however those cameras make it very simple as you just use a handheld meter, transfer the settings, compose, focus and shoot. As it's an SLR what you see is what you get, so you know it's in focus and the composition is exactly what you want.
I also own a 1930s Zeiss Ikon folding camera which shoots 6x9 on the same 120 film, that thing is very difficult to handle as you have to guess the focus and you're stuck with either a tiny and a bit rough "brilliant finder" (a mirror and a couple of lenses, you look into the top) or a crude pop-up frame finder. The lens is first rate but it's difficult to be sure of focus and framing. While it was obviously intended to be cradled against the user's chest in portrait orientation I will be using a tripod next time, and carrying a 35mm camera to use as a rangefinder.