Yeah I looked at the 500 chainsaw closer, and noticed how nice of gun it actually is.
The receiver, receiver finish, internals, bolt finish, mag tube and mag cap are all 590esque.
Plus the barrel is beefed up (not heavy tho) and it has a nice metal mounted white dot front bead.
The barrel is only approx. 14" long, but it's deemed 18.5" because the breacher is apparently welded on.
The fab defense forend and chainsaw handle are all removable, so could be a worthwhile build.