That's what I'm leaning towards bud. Everyone loves a good 'pump' ?
Back in the day I used to run around with my old Super 90 and I had a ton of fun with it. I can only assume the M870 would be even more enjoyable to use.
There's an AA12 at a very fair price local to me (with drum mag) which is making my head turn that's all. But as you've confirmed they are very different shotguns for sure.