"I'm toying with givin' it a 5." ...so did I, and can see other people's justification for doing so. My 2nd round was really an eye opener. Sarah Demar & Geoff Bennett (some of MI's top Pros) were kind enough to let me play with them for few holes before moving ahead, which was very cool of them! Really provided a feel for what genuine skill can do.
As I said (for better or worse): walking away from a course, I have a "feel" for where I think it rates, and try to find tangible support for that number. With all they got right, I really had to look for substantive reasons not to give it a 5.