I've wondered the same about buying a vehicle out of state and how to go about using an escrow service... a legit one and not some front set up by a scammer...
All the cars I have bought out of state I have gone and gotten, or knew the source (dealer, or known seller). This is a consideration, for me, when looking at BaT, as once the auction is over, it's the buyer and seller that figure out the rest of the transaction (BaT does not get involved with the $). The 3 I bought there, were all dealers. Private sales, have been certified funds (not a great option anymore), cash, or an instant in person bank transfer (seller and buyer have accounts same bank, transfer is instant, BoA in this case). I have been intrigued with the thought of escrow, but have, so far, found a way to avoid it. Im sure the service is not free, question is if the fees are "worth it".
I was about to use them for a cross country bike purchase where I wasn't able to be present, but all of the reviews left a lot to the imagination...too many negative reviews to go through with it. Do your research.
I just use a wire. As a seller, my property does not leave my possession until I have funds in hand. I expect to be treated the same as a buyer. You should see my purchase contracts...
When I bought a car out of state I wanted to use an escrow service but heard bad reviews. So instead I mailed out a bank check. Not to smart in hindsight but it worked out lol.