Well Henry Winkler is one to talk! RDA has much better hair than the Fonz
I'm pretty good a telling a season by hair too lol, I think I might prefer season 6 over 5 based on the haircut
I rank the seasons 3>1>2>4>6>5>>>>7
but if I had to rank them by haircut/clothes 1>3>2>4>6>5>7 I was not a fan of the baggy clothes (I know it was a time period thing, I remember thinking maybe he had gained weight by the last few seasons, but then every now and then he would wear something more normal or had his shirt off enough to see he was still pretty fit)