Upload & Sell: On
It's a heavy, well-made modular system that lacks the useful custom functions Mamiya and Pentax incorporated into their latest 645 bodies. The lenses (and @#$ hoods) are larger, heavier and in general more expensive that the latter two 645 systems, used. But, if you want the Zeiss name/designs like the Tessars or Sonnars or Distagons it's your best option, short of using an adapter to drop 6x6 Zeiss lenses in front of 645 bodies, including the Contax.
I find it's also hamstrung by fussy buttons requiring precise tactile input, and pedestrian autofocus that evaporates in low light. The last Mamiyas and Pentax are superior in that regard. It is driven by a comparatively weak 6-volt CR2 battery with limited reserve, in comparison to the other 645 systems' 9-volt setups with ample mAh. That's in part what gives it the power-thirsty reputation, as it's drinking from a shot glass while the others sip their pints.
The vacuum insert is virtually academic by this point as there are few 220 emulsions left.
The 120mm APO Makro is nuts good, better than the Mamiya and the Pentax options for color and detail, and that's saying a lot. The rest of the lineup renders nicely, I think that without fault, they are mostly pin sharp in the center.
I have never used the Fuji/blad H1 so cannot compare the two.
You seem to shot a lot of models/fashion/portrait judging by your website, and often in controlled conditions. Since 645 and 67 use the same film format, would you consider an RZ instead? That system is much cheaper (and more plentiful) than the Contax, though if you shoot outside the slow leaf shutter might work against you if you want to shoot wide open for subject isolation as you seem to do.
Essentially you're buying into a lens system and overall size/format. What is it that the Contax will do for you that other systems can also do, at less cost and with longer likely parts support?
Those are the harshest things I can say about it; it is a really nice system to use, though. Just be aware of the functional limitations.
Phew, that's a mouthful.