I've been to the Hall of Fame in Cleveland. Overall, a good experience. But, the devotion to rap I don't think is "Rock and Roll." Plus, the time I visited, the big exhibit was Bruce Springsteen. I can't stand Bruce. I've coughed up phlegm that sounded better than Bruce. That said, the R&RHOF is still worth a visit.
My favorite parts were some Beatles lyrics scribbled on a napkin and some of Jimmy Hendrix's drawings of college football players while he was in Vietnam.