Thanks for the feedback Buckworks, this is a purchase from a stranger so I thought it would be best to do an escrow. Also the purchase price is 5k so I didn't really want to take any chances, most I've ever paid for a domain.
You can also consider using Transpact.com for escrow.
Not only will you save some considerable expense, but Transpact.com also allows you to tailor your domain/web handover conditions to your liking, so it is much more flexible than many escrow services. Those who have used it for domain/web handover have raved about it.
I think escrow.com are California based. Are you in California? If not think carefully. I'm from the UK but as far as I know different states in the USA have their own laws.
You are using escrow.com to protect yourself but consider carefully if California law gives you the protection you want. Other posts on WM indicate that possibly using escrow.com is useless unless you live in California.
If the amount of money you are talking about is US$5k then forget using an escrow company altogether. Talking to a lawyer for 15 minutes will cost you $$$$ and you will be no better educated after it.
My advice is greater then $150k then think about the legal aspects. Less than £150k then use your own instincts. Lawyers will suck you dry for smaller amounts and are not worth the effort.
follow up: things went fairly well, transfer was completed. my only complaint about escrow.com was that they allowed the seller to badger them into starting the 24 hour buyer inspection period prior to the domain being completely transfered. That could have blown the deal, if we had not had control of the domain before the inspection period was up we would have had to reject the transaction. If that would have happened the domain could have been in limbo for 60 days per domain transfer rules, which really would have effected the seller more than us.