Can you wait or do you need a machine immediately. There will probably be some lead time before the new machines are delivered.

If you have a computer you can still use the move is definitely to cancel. Then either buy the new shiny or buy the older models (unused or refurb) at a reduced price. These M processors are so good that for me, the ones currently shipping are perfectly fine.

Depends where you live and how long the delay is.

The perf gain should be circa 20%, but in Europe prices got a noticeable bump due to the strong USD (relatively).

You have 14 days to return it no questions asked. So no worries either way.

Yes. A good day for you to hear the announcement :)