Trolling your thread, work for another company by wanted to chime in. I had company car for years first year now with an allowance. I'd take allowance any day of the week. My company is a little different - we get a 650 allowance (taxable) and a .19 reimbursement for mileage (non-taxable). I've got a large territory and drove 36k miles last year.
Here's why it works for me. I bought a used, still in great shape Mini Cooper convertable - great on gas. At the current gas rates I make .10 a mile just on mileage = $3600.00 last year. My reimbursement more than pays for my maintainance, ins and monthly payments. Now, here's where it becomes awesome for me. Because the IRS reimbursement is .575 and I am only being "partially" reimbursed .19, I get to claim the difference as an unreimbursed business expense. Bottom line is even though I come out on the plus side even before tax season and get to drive a car I enjoy, I have a $13,860 (36k x .385) unreimbursed business expense deduction to take this year! However the company sets it up, a smart rep will make out better with allowance vs. fleet.... unless - you go out and lock into a three year lease and get laid off; you buy something expensive and get laid off; buy or lease anything expensive at all even if you keep job; you buy something that has shitty gas mileage.
Buy used, dependable, good gas mileage, low maintainance and something you enjoy driving. Let everyone else have the four door sedan the company chooses for you.