Just an FYI, we have had issues with almost all of our 750 viewfinders. The screws holding them are all coming loose. Your horizon will be all screwy after this happens, you can tighten the viewfinder, but it will come loose again. Lock-Tite seems to be the solution.

Update:

One of our viewfinders actually fell off, two more are loose. It this a common problem?

Or is it just the batch of cameras we received?

I've had these same problems starting with my JVC DV500U cameras.
Lock-Tite is the only solution I've found that works.

Our engineers have found that loc-tite is the only temporary solution as well. It would be great if they would upgrade/redesign the viewfinders, maybe with a larger viewfinder! :)

The only problem I've had with my HM700's viewfinder is due to me catching it as it was being blown over one day. :-) I should get it fixed now we're in the football (soccer) off-season in Ireland, but it managed six months of being duct-taped into position without any loss of functionality. I'm fairly pleased with the build quality of the camera as a whole, it's taken a couple of years of abuse from the top of builder's rigs masquerading as tv gantries without complaint, even when wrapped in a tarp as the only rain protection it gets...