Only company I can speak about is Tri-State.
I've had two different 3 year stretches with Tri-State, none with any other expediters. My experience was that they pay what is owed, pay when it is due, and arrange for payments of some expenses by settlement deduction when you agree. Rigging a unit for expediting was done by them and costs stated in advance and deducted over time from settlements. Orientation was straight-forward and honest. Only problem with pay was when the customer refused to pay agreed amount to Tri-State, then your pay for that run would be adjusted accordingly. Didn't make me happy because I agreed to run a specific load for the offered price...but the contract with Tri-State stated a certain percentage of the amount received by Tri-State, so if customer paid less, I got less. I don't believe that same customer is still in their pool of shippers, and it was a rare happening in any case. I had many loads where I was paid more than original offer I had accepted, so that was good.
Sometimes, but not often, actual miles were more than offered miles, but I should have checked actual miles before accepting the load. Dispatch was friendly and answered all questions to their knowledge. However, I soon learned that I had to ask the right questions...example, Do we get loads out of that area? Then have to continue with Do we get VAN loads out of that area? Do we get SOLO VAN loads out of that area? WHEN did we get SOLO VAN loads out of that area? Get the picture? If you ask, you would get an answer, but you had to ask enough questions. Tri-State personnel were available to talk with, mentors were available for tips and guidance, you weren't bothered if you didn't want to be. You can move to any area of your choice to get a load, sometimes under bonus, sometimes on your own dime. They are far from perfect, and changes happen as the economy changes, but if I go back into the business, I'd certainly consider returning to Tri-State. Some other firms look good too, but I'm used to Tri-States warts and can live with them. My info is not exactly current, so I think anyone needs to get current answers and opinions from the companies and their drivers, some of whom are on EO.