You're right, it does involve a lot of personal preference as well as your needs. The great strength of a single lens reflex is its ability to usually do, if not the best job of anything most easily, then, at least, a fairly decent job of it—its sheer versatility. You've said you do a bit of everything. This tells me an SLR could be a good choice. Close up; long lenses, a Hassy will acquit itself well. And if you found a Bronica do-able there's no reason why you'd have any more trouble with a Hasselblad.
On the other hand, rangefinders have their own virtues, too. A Hassy with a waist level finder and say 80mm Planar is actually a pretty wieldy camera. But it will never be as quiet as a RF, or as rapid to focus. And unless you accept the weight and bulk of a prism you'll have to deal with the image reversal. For street imaging a RF definitely has some real advantages.
Short of having one of each (not a bad solution IF you have the cabbage) it's a case of prioritising your needs. To mention the obvious—if mid roll film changes are an advantage, naturally, you would have to go with Hassy. It's one point the Mamiyas simply can't match.
If that's not an issue, as much as I love my own 500C/M, providing long lenses or close up work aren't major factors in your choice, I do wonder if the 6 wouldn't be the way to go for you? You mentioned always being "on the go". The Mamiya is probably going to be faster for you to compose with and to focus with, as well. If you can accept it's close range limitations as a RF, and inability to mount very long lenses, perhaps it might suit you well?
Just to complicate matters further, there's also the TLR configuration that shares some strengths and weaknesses of both SLR and RF. But (more often than not) you're going to be locked into a single focal length and quite possibly a reversed focus screen image too (there are some exceptions of course, depending on which make and model is involved). And TLRs can be a love/hate thing. I have a Hassy and some Rollei TLRs and use a 35mm Contax RF so, personally, I don't mind using most camera types—but I'm not you.
Love to know what you end up going with.