Have the seller go over it VERY carefully and note the dings, dents, scratches, etc already there. When it arrives, if you question anything, call them immediately and discuss the condition of the vehicle.
Remember that a lot of these companies you see on the web are just contracting companies that farm your "job" out to private drivers or regional companies. That's where the problem lies sometimes.
My brother shipped his car (nothing special, a nice newer Hyundia) from Grand Rapids, MI to Raleigh-Durham, NC about a year ago when he took a new job. The transporter showed up, took the car, and off it went.
Pete and my folks drove down with all of his stuff and Pete started awaiting his car. Showed up a day after he was supposed to get it...no biggie.
Then he immediately notices damage to it. Scratches in the paint, one of the bumper fascia isn't sitting correctly, smashed mirror, etc. The driver tried to play it cool like he had no idea how it happened but Pete luckily actually paid attention to his car (not a car guy at all) and started complaining ASAP.
The driver got very nervous about Pete reporting it to the contracting company and ended up paying to have it fixed...
...but then would balk at the prices to fix and replace stuff the correct way. Guy kept trying to cheesewhiz Pete with cheapo fixes and such. However every time he threatened to call the shipping company the guy would quickly start counting out his money.
If you have any trouble call the shipping company immediately. I'd also make sure and look under the vehicle before the driver is gone as I have heard stories of them strapping/chaining the vehicles down incorrectly or with so much tension that the frame, suspension, and/or axles bent.
Not trying to be Mr Negative but after my brother's experience and a few other stories I've seen on another site I'd prefer to make the time to go and get the vehicle myself provided it can make the drive.