Just make sure that there's an escrow that will middle in every transactions you made so that you can assure your safety as well pick those trusted escrow with good experience in the said job and don't pick those cheap guys telling that they offer a escrow service to add more security on transactions.
What is an escrow? Ive never heard it before but looks like its a middle-man something like that?
Yes its a middle man which can make your deal more secure and to understand how this things works better you read this thread
https://bitcointalk.org/index.php?topic=276897.0 since that one explains how it works. Also you can see the list of trusted escrow so better go on the list and avoid picking other users who's credibility/trust are not yet tested.