I don't think the Strombergs are really that much shorter Doc. The dashpot knob of the Stromberg ends up being almost as tall as that on the SU in the end. I think when you throw the air cleaner/filter housing into the equation the Strombergs end up being a bit shorter though.
Regarding the diaphragms, I have yet to have one fail but everyone has told me that the new ones aren't made the same as they used to be. If the new ones are coming from China I certainly can understand the problems people are having with them. A buddy of mine prefers the Strombergs because in his eyes, when the diaphragm fails you know what's wrong and can easily fix it yourself (his words, not mine).