Just wanted to throw in my thoughts.
I have had my 590A1 for a little over a year now. Shot it with the original stock for a bit then picked up a Hogue (12" LOP if I remember right) to make it a bit shorter.
The Hogue felt good but would start to hurt my wrist some after time.
I went back and forth trying to make my mind up on getting a stock with the pistol grip. I thought I would never know until I tried it for myself.
Picked up the ATI
Went on very easy. The instructions might need to be updated because it was telling me to hold bolts that weren't there. Anyway, a very easy install.
It feels very natural to me now. I feel I have more control over the gun and I can really tuck my elbow in now.
On Christmas I got to shoot a few boxes of 00 Buck and a bunch of Bird Shot.
The 00 Buck felt like Bird Shot and the Bird Shot didn't feel like much of anything.
IMO I could stay on target a lot easier making follow up shots really quick.
So far I'm really happy that I went ahead and got one to try out. I know they are not for everyone but I think it was a wise choice for me.
Can't wait to go shooting again.