My company has a bunch of 550's with the V8. They seem to be a lot more reliable then the diesels they replaced. They seem to have good enough power. Terrible fuel economy though. 7-8 mpg. The guys have to fuel them every day. They have a GVR around 16k For comparison I drive a M2 Freightliner with a 6.7 Cummins and it gets around 10mpg. 26k GVR.