re: Been there done that
And go to Mars.
And after just one 3 year long flight to Mars, the same Been there done that argument will rise. Only 4 astronauts (instead of the 24 Moon astronauts, 3 of them twice) will have visited that planet.
The Moon is a compromise in many ways: like Mars, it is another world but like low earth orbit, it is close to Earth.
And Mars is too alien to be colonized (too low a gravitiy, too much UV)which makes me believe O'Neill's space colonies will sooner or later come back in the pro-space groups.