I think the SPG surveys are actually pretty good. As some have pointed out, attempting to benchmark every stay against expectations is not the most sensible approach, but they're certainly leagues ahead of BA's customer surveys.

I can imagine that having someone at the property reach out to you after a survey might sometimes come across a bit weird, but I'm all about service recovery and so if they are belatedly able to acknowledge and address criticism I'll usually give the property the benefit of the doubt.