We replaced Chris' 13 year old MacBook Pro with the new MacBook Air 15" recently. I had expected the migration to be a bit bumpy ...
First bump was Migration Assistant refused to assist as the old MacBook used a case-sensitive file system and the new one did not. That Migration Assistant made no attempt to help in the transfer as our first experience with the new machine was really disheartening. So everything needed to be manually copied over.
Second bump was that the old MacBook file sharing would not turn on. No idea why. (It used to work.) This meant having to use an external drive to relay content between the machines.
We decided to use iCloud for photo and document storage. Unsure if that was the right decision. Anyway, a few days later the uploads were complete.
Third bump was Instagram on the iPhone is not showing any photos from before a few years ago for use in posts. Chris' business relies on social media so this is important. Maybe it is a syncing issues and will go away soon. As a developer, my fear is that the app is showing the first 16,384 photos! (It would be ok if it showed the last 16,384 photos.)
Fourth bump was when Chris finally started using the machine the WiFi was unbearably slow. It took me a few days to discover that this is not so uncommon and is related to AirDrop and AirPlay. I disabled those features and networking went from 1 MBS to 30 MBS. Hopefully Apple will fix this soon as we have found AirDrop to be very useful.
Chris has me to help with this transition. What do others do who don't have a reluctant home sysadmin? Again I find myself embarrassed and exasperated that my profession continues to make these tools so hard to use. Jef Raskin was right.