I saw the Knoxx stock and fell in love with it. I've always wanted a pistol grip shogun, but folks with more experience than me told me to "get one with a stock". This was the best of both worlds. I went to my local candy store looking for Mossberg 500 and I was going to order the Knoxx. They had this girl instock and when comparing the 590A1 and the 500 there was no comparison. They also had a Knoxx instock. It was more than I'd intended to pay, but this shotgun will be around LOOOOOOOONG after I'm dead.
The Knoxx works as advertised and recoil is significantly reduced. However the drop in the comb is now different and I have a hard time using my ghost ring sights. I may go back to orginal configuration. More shooting will have to be done.