I've had mine since new from 1992. As you must know, given your desire to own one, it is an astonishingly good camera and lens system. I will never part with it. But, I baby it, especially its notoriously fragile film advance lever. I know mine well and I hope it will last many more rolls, but I don't think I would buy one used today (unless I knew the camera or seller well). As you say, they are too much money for too much risk. It's hard enough to service an old mechanical camera these days. Almost impossible for an electronic one.
On a related note, just yesterday my son and I "unbox" a legendary Nakamichi Dragon, purchased a few years before the Mamiya. (I was single in those days and prone to shopping therapy). The Dragon had been sitting idle for at least a decade. Anticipation was high, but there was no power to the control panel. The channel LCDs and counter light, so hopefully it's just a fuse. But if it's more, there is little I can do about it. Find one that works and they are a small fortune. "As Is", and you can have it for less than the Mamiya.
Without a doubt, a great camera, but be wary of old tech.