I just did the math on mine through our vendor. I have a 2016 F150. I've incurred $56,000 worth of expenses. Gas, maintenance , cost of vehicle. If I had my own I would have broke even. I would be the owner of a high milage mileage vehicle, so I could have come out ahead.
The difference is I can drive my company vehicle whenever and wherever I want. I've driven it from Texas to Tennessee, to the beach a couple times a month. No way the company would pay milage for my personal vehicle for personal travel. So it depends on the package you get. Plus I'm paid by the hour so anytime there is service or an issue I'm not losing time.