Too many variables here, in what a "company car" means.
a) Something the company owns / leases / insures in which they cover all gas, maintenance etc, with the exception of personal miles which you have to report and be taxed upon. It's not yours per se, so resale at the end of the lease is kind of irrelevant to you.
b) Car allowance in which they provide you a stipend to cover car, depreciation, maintenance, insurance etc. In my experience, you would then get reimbursed for business gas, but not mileage, as the IRS mileage rate is designed to include things that are covered in the car allowance. Tax laws are a little more particular with this angle to ensure the allowance stays non-taxable.
I've done it both ways. My preference is for the company owned model, where I don't to have to think about it. I total it it's on them, I quit, here are the keys. Engine self destructs 10 miles after the warranty. Do you want to fix it or buy me another one? But if you already have a suitable vehicle particularly if you are making payments, the allowance can make financial sense.
Unless it's a small mom and pop company, any larger company is likely going to have restrictions on what kind of car you can have as they want to ensure what you drive represents the brand appropriately. They may even restrict it if it's a car allowance. Ie, must be within X years old, must not have signs of visible damage, etc. Must have four doors (assuming you take clients to lunch etc.). It must be a truck if you are a CM or something and your employer wants you to be able to run to carry material on occasion. Luxury car, maybe not, as it may say to your clients that your company is a bit "too" financially successful.
