WHile I do not own a 500 Magnum, I have fired a few hundred rounds out of two different guns. Honestly, UNLESS you are a handgun hunter or you live in the wilderness, I see little use for one.
I severely damaged my hearing (even more than it was already) because of the 4" ported barrel at an indoor Range a few years back - and I was wearing both plugs and a head set together. Not blaming anyone, as I should have been astute enough to stop but did not.
The S&W 500 Mag is a hoot to shoot for a few shots, but the ammo is costly, the noise is unbearable (indoors) and other than for wild game I see little reason to own one - but that's just me.