Interesting... most technology is gets around only slowly, with the impact becoming clear only after a while. The biggest exception must be the atomic bomb - at least for the outside world. That's one way to think of it: what would have happened if they'd announced the A-bomb a few months in advance.

Alternatively, if the development is done by some relatively unknown group, the reception may be more like what you'd get if you'd announce that you built a machine that will solve the world's energy problem -- disbelief and skepticism.