I like Model 21's!
Have owned a few and hunted and shot clay birds with them.
Still own a Custom Shop 'Custom Grade' 20 3" and a CSMC 'Baby frame' 28 Grand American.
But the OP asked about a gun and we get the same old Posts about Model 21's that I have read 'ad naseum' over the years.
Even though i like Model 21's, the short of it is that the gun in question is way overpriced, not very suitable for waterfowl or anything.
Move on!-Richard