All I can tell you is what I hear on the street: Freightliner is on the below average side of quality compared to other brands.
M/B diesels are nice, but I gotta think they're expensive to work on compared to IH or Cummins or Detroit. Probably a lot like CAT.
My gut feeling would be that it would be fine as a new truck under warranty, but once it expires, it could be expensive to repair & maintain.
A company I buy lumber from stopped buying IH and went to Freighties. They don't like any of them and are now buying IH again.
Another yard I do business with has 2 of them, both less than 4 years old, they look really bad already. Kind of like they're falling apart.
I sat in the cab of their tandem and thought it was very nice inside. I also think they're good looking trucks.