My .02. I have a mossberg 590A1 and love it. It hold 9 rounds and has a 20 inch barrrel. Some of the other 500 varietals have a shorter barrel nad give up a round or 2. If I need 9 rounds I got bigger problems (Zombies duh!!!) The Remington 870 is the other highly touted HD scattergun. Again I feel like for the price the Mossberg is def the way to go. Mine has held up to some rough treatment and still handles flawlessly.
Good luck and when you decide post pics! I want a coach gun just for the heck of it, so if you can get both. Dont try to justify one to serve double duty.