This morning I received my new 2018 Air, used my time machine backup. Everything went smooth with the backup.
I have really 0 lag and hiccups this first day, and boots go pretty fast.
To be honest, I am pretty amazed by the speed on this first day after the time machine backup (indexing)
I like my new Macbook Air, especially the lightning fast TouchID (faster than any iPhone with TouchID I had in the past)
The only real negative is the screenbrightness/colors
Also, the keyboard I find much better than the 2017 Pro