Interesting reading all the comments. I guess I am one of the lucky ones. I was able to upgrade with no issues at all. Took a few days for everything to settle down. But the ship is sailing well. I checked a bunch of mail boxes, some dating over 10 years, all the mail looked good to me.
There are so so many things that Apple does well, but Maps and iWork, well, these are not one of them.
Just leave this stuff to others and work on the good things