Aside of the golden period of press cameras and folders, when in comes to 1980's until now (may call it "modern") there aren't that many MF RF's.
So I'm paying more attention to those who suggest the aura of film in MF captures a certain quality of light that digital doesn't. Sounds credible... even it's not. Prices for a Mamiya M645 are stunningly low for what it "seems" you get.
In a way, yes. But not the light itself but the optical rendition. Medium and large format require longer focal lengths for the same FoV, together with the different DoF characteristics. (40mm 135 = 90mm 6x9) Pair it up with the large neg smoothness and you do get the "Medium format look".
My old Fuji Texas Leicas only cost a few hundred dollars, and the glass is not costly. These are very durable cameras that are very basic.
BTW 645 to me is kinda inbetween and for me medium format really begins at 6x6. 645 is such a baby step. It is really hard to beat the big negative, except with a bigger negative.
Cal
645 is quite controversial but actually a useful format in some situations, and Fuji did have a quite well laid out 6x9 + 645 complementary line. It boomed and still is very used in the wedding crowd for its shot/roll + MF characteristics ratio.
There was a thread around the forum about the low cost of Fuji 6x9's, which we deemed to be around its concept of not so attractive functional spartan camera.
In 2012 I started to dabble which MF I'd get and decided upon a GW690(III), mine was quite lower priced mkIII user camera and actually around those years their prices dipped quite a bit. I compared at the time of purchase (2014) and there wasn't anything with the format bang for the buck (6x6+), and to top it up, modern.
I very well might have read this thread back then, and saw lots of support for these cameras. Add in some confirmation bias and convinced me to get one. 1460g for such a neg isn't that heavy, and they are large (35mm form factor must play a lot in them being seen as ridiculously large).
There is the curious situation of some models becoming cult and very appreciated (Rolleiflex, Hasselblad, Mamiya 6/7, Pentax 67(II) ) and having crazy prices lately. For the Mamiyas I recall seeing kits at 1200€ in 2014 and now it's around 2000€. Other cameras (Say Mamiya 645 and RB67) must have lots of ex-pro surplus and less pizzazz to them so go cheap.