Avantages
With the dispatch system in place, its one of the quietest jobs in town unless you want it not to be. I worked their prior in the days of the old trunk radios, and the new ways are definitely better. No boss standing over your shoulder breathing down your neck, get to see many different companies (not a bad place if you are looking for another job and need something between), and some opportunities to move up within the company if you want.
Inconvénients
If you work as a courier and never become a trainer or never get involved with the office staff your job will be just that, courier. No benefits, 1099 headache, can be difficult to manage expenses (and big ones can come out of nowhere and hit you hard). Many problems and headaches with actually getting paid the extras like time, weight. Need to be very careful in who you speak to, because you never know who they are really within any other company.