I've had an 8 3/8" for about a year now. It's a little muzzle heavy, but balances nicely for something that large and heavy. Good trigger. Reliable. Shoots pretty well, mine especially with the Hornady 350 grain XTP's (published velocity 1900 fps).
A buddy of mine just got one of the 4" models. I really like the way it feels and balances in hand. Not that bad to shoot either.
For me, the 500 is a little more comfortable to shoot than my .454 Raging Bull. The .454 is a high pressure load, and makes my shooting hand sting when I shoot it. The 500 doen't make my hand sting, but it does come back at you harder than the .454.
For me, the most painful thing about shooting the 500 is the price of the ammo. You really have to reload to be able to shoot it.