The only reason I had a Mamiya C33 (or some code like that) was because I couldn't afford Hasselblad at the time. It sucked, especially with the longer lens which was all I had it for; the accompanying Rollei T I had was a dream in comparison.. However, the 180mm was a beauty. Once you've had slr you won't want, ever, to mess with parallax problems again in your life. Unless somebody offers you an M9.
I wouldn't worry much about the argument of 6x6 v. 6x7 either. In my first experience of the latter, a Bronica GS (?), and with a second venture with the then new Pentax 67 11, it was a doubtful advantage as I found the edges of both systems pretty awful. Worse, with the Pentax, the shutter always bounced as much, at least, as the mirror, so MU solved nothing.
In comparison, I loved my 500C and 500CM where MU did work and the shutters were pretty smoooooooth. Anyway, the two were objects of beauty in their own rights!
Rob C