Honestly, I would avoid Prime at all cost, period. Their drivers are always complaining how they're starving. You got to remember, those are lease trucks, meaning you pay a lease on them. They are cut way back on speed, so it takes that much longer to get the hauls done.
I got behind a Prime truck the other day on the interstate, and the damn thing was only going 55 mph. I thought they were at 65, but I'm wondering if they were cut back even more.