I used one for the 870 for over a year. Quality is good, durability is so-so. I broke one of the four tabs that go into the receiver while it was off the gun, and then the tab that holds the buttplate in, also while it was off the gun. They replaced the buttplate for free and with no hassle, and I never noticed the receiver tab until I sold it.
Since none of it broke while on the gun or risked it coming off the gun, I really have no complaints with the stock. The only thing that bothered me was the grip being on the boxier side, and a Benelli grip fixed that for like, $15.
It's easily my favorite pistol grip stock.