Thank you all for your replies.
First, both cameras have waist level finders, but Mamiya also has a very strange looking p-of-sorts - it's assymetric and protrudes on one of the sides. Very strange feeling and handling when that thing is on, so I will definitely stay with the WLFs, at least for start.
Mamiya also has the side grip, which I didn't find helpful at all. It might be that all I need is a bigger bicep, but I don't have it yet so the grip is staying at home.
Second, I have done about half a mile walking around the apartment with each camera, trying to focus. It was a breeze but worked a bit faster with the Hasselblad because of its bigger and brighter screen. I didn't try to focus close and don't intend to with first couple of rolls.
Overall, the 500c feels simpler and easier to handle but that is expected considering where I am coming from. It's also had a CLA so I know it works as it should.
Then comes the big bummer - I can't handhold the Mamiya. It's highly unstable and tilts every which way, but that could be due to my 35mm-itis which makes me hold the camera in my left palm and do the work with my right? I might need to nail it to my chest so I can have both hands free... or I should just let it hang on the strap.
But then, I intend to use a tripod for at least some, if not all, shots. Also, the Mamiya is making me much more curious. On top of that, where I live, Mamiya would be less conspicuous. Heck, I am sure that 80% of people wouldn't even be sure what I am looking at, and why.
It's a conundrum, really.