choosing a company

They are but you still do the math to track fuel mileage and other mileage costs that way. There is also a guaranteed mileage rate if you take a load that is calculated at a lower rate than the guaranteed rate.

 

Which is better?cpm or percentage

 

As a rule of thumb, percentage, but this is assuming they have a reasonable rate to base a reasonable percentage rate on. 27% of $2.00, good, 23% of $1.45 bad. A carrier will rarely tell you what their rates are up front, and you will not get a percentage of any fuel surcharge. You will have to trust what they tell you as an expected "average" and hope for the best. But if they bobtail you 400 miles for a load (on percentage), chances are you are not going to get paid for the bounce and will have to consider this aspect, too.

There are a lot of question marks in doing percentage and mostly it depends on the plan offered and how it's structured. With mileage, there little room for playing around with the numbers outside of hub vs. computer miles which is a given.