I've been present a three boat surveys so far and I have to tell you I wasn't that impressed with any of the surveyors. In one of them we pointed out every major defect that was found _after_ he was done inspecting that area and declared it good. This included a rudder that needed rebuilding....
On the other hand I totally lucked out on my
rigging surveyor (but it was on a strong recommendation from a friend who owns a similar boat). I suspect that finding a good surveyor is roughly as hard and as golden as finding a good doctor or dentist.