30gh @750w is way over optimistic. knowing how A4 ended in fiasco, my guess is it's going to be 20gh @ 1500w i say this because they haven't tested the chip yet and everything they advertise is based on simulation tests.
Agreed, there is a huge difference between how a single chip tests on a bench vs how it runs packaged on hash boards with other chips. We saw that pretty clearly with the A4 that the chip by itself appears to run very well, but not so hot when put on hash board with other chips. Hash rate dropped and power consumption went up.
So it would be wise to wait and see what a running A5 looks like before thinking of spending any money. Regardless even if it ran according to the spec they posted I would not spend 10k for one.