We've sold three so far, and done one migration. So far, trouble!
But not the machines. Rather, Big Sur is not done cooking. We had a bit of trouble with the migration, and we bricked our floor model 13" M1 MB Pro. Still working on a fix.
The good news: The silly things are fast as hell! Even the biggest, baddest apps open within 2 bounces, and they just fly through everything. And, so far, we have no idea what the fans sound like.
Oh, and it's absolutely wonderful to hear the chime, again!