Migration to new MacBook Pro
Usually when migrating to a new computer whether it is with migration assistent or other software, it will always cause your hard drive to be fragmented which will cause your computer to run slow. In some cases it can be very fragmented. I would recommend running DiskWarrior this utility is incredible how much faster it can make a computer, especially after migrating to a new computer. P.S. in the future I would recommend using Carbon Copy Cloner for all of your migrating, it is a lot easier and safer way to migrate.