I keep a Remington 870 express tactical upstairs. Picked it up used at Gander Mountain for $350! Excellent gun, even shot skeet with it a couple months ago (after switching the choke out).
Remington 870 with Knoxx stock on it. Stock will take out recoil of .12 guage and all the goodies you can do to the 870. The winchester 1300 is also good. I do not ownthe saiga yet but have been looking. i own a benelli M1 super 90 and love it. Kel-Tec is trying to make a .12 pump with 2 7 round mags. Early pictures look very cool bull pup design