One more vote for sticking with a plain CYL or ImpCyl barrel on an 870P and buying a variety of buckshot loads. You can pretty well choose your pattern (large, medium or small) by choosing your load these days, and a CYL bore barrel is a lot more versatile for everything else IME.
Uncle Hans & Co. do excellent work, don't get me wrong, but improvements in ammo have pretty well overtaken internal barrel modifications including VCS and choke tube installation. And this is someone talking who has spent several hundred dollars in 870 barrel mods (forcing cones lengthened, choke tube installations etc) over the past couple of decades to shoot buckshot better. FliteControl wads now make all of that a wasted investment, but it worked for the years before FliteControl was available.
Thing is, you can change your mind at any time, no matter what you start with, and add another separate barrel with whatever configuration you want to your existing gun. I personally wouldn't spend the money on a Wilson anything as far as a full shotgun offering goes, but I do have a few of their accessories here and there. Buy a good 870P, new or used, as your base gun and work from there as you learn what works best for you.