Yes, they have been a band for longer than I have been alive.
Yes, all their music does sound the same.
No, they have never (unless you count the song "Ride On") ever put out a ballad.
And yes, they still put on an amazing show!
I'm partially deaf. My voice is shot. But it was all worth it to see AC/DC for the first time in more than two decades of trying to get tickets!