I think you made the better choice. Your Mamiya's film path has no bends between the supply spool and gate. The Rolleiflex's goes around a sharp 90-degree turn first. Unless one shoots an entire roll in rapid succession, typical 120 acetate film base takes a "set" on that feed rollerand then becomes far less flat when advanced to shoot the next frame. You done good.
Agree completely on the bending issue. In fact, this was one of my two main reasons for choosing the Mamiya.
I've owned (as the original owner) a Yashica MAT 124G since they were introduced, so I have experienced the 90-degree issue first hand. In that camera the roller is a tiny 1/4-inch diameter guy. He's positioned to ideally fall between frames, but the issue remains, especially when the frame spacing is not perfect.
After having seen blurriness in a few frames* I began shooting only entire rolls. That cured the problem, but at the obvious cost of a little inconvenience in the Yashicas. And with a straight path, the cost in the Mamiya cameras of a larger camera body, which with my larger grip I actually prefer. The 124G was always a bit precious in my hands.
The other reason was, of course, interchangeable lenses. I currently have the 55, 80, 135, and 180 samples, all as latest blue dot shutters. In the near future I am going to fill in the remaining three (65, 105, 250) for the full set. Rolliflex can't touch this capability. And as I mentioned, the lenses are well-regarded. Only the 135 falls down to just average.
The choice of Mamiya over Rolleiflex was based entirely on capabilities, not on price. But the price difference is certainly not to be ignored...
Ken
* Note to 'ghart': The blurred frames only seemed to occur for me when a partially exposed roll was left in the camera for an extended period. Meaning, as I recall, several months on the shelf over one of our typically long winters around here. For more frequent users this problem may never occur.