Well...took three hours to get it to run at all. Apparently you need to start an account, then start Fusion, then go back to your account at which point it starts a cloud folder, then start Fusion again or....something...and eventually it will actually start.
And it is sluggish. The camera keeps moving randomly because the software is just too slow to keep up with itself and know if you are just moving your selection pointer to a new selection, or trying to move the camera. That's on a dual i7 with HD Graphics 4000. Not the greatest system, sure, but a mid-range laptop that's not much more than a year old. And if your general-distribution software doesn't run on that, you may want to rethink what you mean by "general distribution."
I'll keep messing with it, but I have models that need to be done NOW.
More findings. It is a little laggy, but the camera issue is because Fusion's code base apparently over-rides the Mac for reading trackpad input -- regardless of how the preferences in Fusion are set up. The Mac OS is of course tuned to the Powerbook...and Fusion is not. So if my thumb is within a half inch of the pad (aka is within my usual mouse position) Fusion will read it as a two-finger swipe instead of a cursor move. If, on the other hand, I use two fingers, Fusion will read that as a three-finger swipe for its purposes.
What did I say a few posts ago about 3d softwares violating the GUI? The only thing I can say in Fusion's defense is after you've learned a completely new muscle memory, it appears you would be able to navigate the 3d workspace very efficiently.
I still wish I could lock rotation. Rotation is essentially useless to me when I'm in an ortho view trying to snap to a reference image. There is a reason why rotation is usually harder to get to in most 3d navigation schemes; it is used so much more rarely. Alas, not in fusion. Since it reads any two fingers as a camera control, any shifting of those two fingers relative to each other is read as a command to rotate the view in plane.
I think, all in all, I prefer the Carrara and DAZ scheme where you implicitly hold down a key (usually control) to change the behavior from free-moving mouse to camera control.