Looking to Buy a Commercial Truck?

I am looking into buying a truck to run the Western Part of Canada. I was trained on a Volvo and have driven Western Star, Freightliner,Kenworth. I am trying to find the truck that is going to be the best fit for Power/mileage and Maintenance. I will be hauling double axle 53ft Reefer units only. I have been looking at the Volvo line of trucks 670,780,VT880 series as well as the “New 09” Mack CXU613. I have been told that the Mack has lots of power but is notorious for low fuel economy.It shows a photo with 6.7 on the mpg display. I have heard a lot of drivers on Satelite radio talking of 7-7.5 as a fuel consumtion rating. I am just trying to find out what may be the best truck for me to start out with.I really like the safety rating of the Volvo and also the driver comfort/use factor.However the new Mack is very functional for the driver as well.

Any help would be appreciated.