Think it would be a good idea to review agencies and houses as well as individual providers? Seems to me that an evaluation on their quality of service--courtesy, cleanliness, reliability, discretion, reasonableness of fees, overall quaality of providers, problems like bait and switch might be even  more important than that of any individual provider that might be on their staff, This would be especially important in deciding to take a risk on a new, unreviewed, or infrequently reviewed provider.