I -WOULD USE- migration assistant to "move your old stuff" to the new Mac.
Important question:
Do you keep a backup drive ??
The best way to migrate is by using an external backup drive.
The best backup to have is a "cloned backup" created with either SuperDuper or CarbonCopyCloner (both are FREE to use for this if you've never used them before).
A time machine b/u works too, but things may actually go faster with a cloned backup.
Just before the new Mac comes:
Perform a "final backup" from the old Mac to the backup drive.
When the new Mac arrives:
Take it out of the box and set it up on the table, but
DO NOT PRESS THE POWER ON BUTTON YET.
Connect your backup.
NOW press the power on button.
Begin setup.
When setup assistant asks if you with to migrate from another drive, YES, you do.
So... "point the way" to the backup drive and give SA time to "digest" everything (it takes a while).
SA will present you with a list of things that can be migrated.
I suggest you just "migrate it all".
Let SA do its job -- again, will take some time.
When done, you should see your old login screen, as before.
So... log in and "look around".
Good luck.