throw in the fact I live in NY. I have to either buy ammo from a shop or order from a select few retailers and have it shipped to a FFL who will charge a fee.

From the tests I have seen and the little I have actually witnessed the Flight control it will usually edge out the vang comp system but not always by much. If you want to shoot a lot and buy ammo I would just get your gun done. If you arent going to shoot much and the FC stuff works in your gun then suck it up and pay the premium for a case or whatever quantity you want to stash and never worry about it again.

After my tests I decided that I dont need either in home and can do alright outside too. I love the ability to take nice aimed shots at 40-50 yards with buckshot but realistically I just dont need it for my purposes.

I had my 870 backbored and ported by Hans Vang years ago, I like the fact that I can use any ammo and keep the pattern compact.