I would have. I've handled both extensively, and the Mamiya is far better suited to my needs.
If one has experience with both, they should use that experience to inform their judgment, because both are excellent, professional quality options, but they differ in many important ways.
Back in the day, I sold more Hasselblads than I did (the earlier version of) the Mamiya 645 options, but I dealt with customers whose needs matched one rather than the other of both options, and I had no qualms trying to match them up with what suited them best.
For those who don't have the opportunity to determine that suitability ahead of time, I'd suggest moving carefully, because investment in either option with the lenses you might want is a substantial cost, and you might find yourself unable to change your mind easily thereafter without it involving a substantial amount of lost money.
There are many people out there whose needs won't be best met by either of those two options - medium format SLRs are great, but the functionality and flexibility they offer come at the cost of weight, size, complexity and cost. If your needs differ - e.g. you are much better served by a rangefinder or a TLR or even a medium format view camera - try to match your needs, rather than buy because of the name on the front of the camera.