Pros
If you have the knack for it, the actual driving experience is second to none. Good pay, but you will earn it. The immediate leadership is fine to work with although they will work you as hard as you let them. If you are just starting and are looking for a way to get you CDL this is a good way to do it if you can tough it out. As long as you stay out of the politics and stay under the radar, you shouldn't have any problems. Just watch your mirrors going down the road.
Cons
They will call you night and day to cover runs if you have the hours or not. If you get the newer equipment that's good, but usually you will get stuck with the scraps and end up breaking down all the time. Very difficult trying to have any sort of home or social life as you are either on the road or too tired to do anything.