Hehe I've used several of the commonly found folding stocks over the years in my quest to find the right compact shottie for me, so I do have some opinions on them:
The ATI top folding stock is ok. I used one on my 870 for several years. My only complaint about it was that it does have sharp edges that you will need to file or sand off. Mine in particular cut the first knuckle of my thumb the first time I went out shooting with it. For the price, it is a decent stock that is streamlined against the shotgun and reasonably solid to shoot. It is not particularly quick to the shoulder though.
The Choate I found to be clunky and awkward. Probably the most solid of the bunch, but I didn't like the aesthetics, and like I said, awkward feeling.
The Remington steel top folding stock is ok. My major problem with it was that the one I had was rattley and felt loose. Could have just been the one that I had - it was police surplus - but I was never completely confident shouldering it.
The Knoxx Cop Stock is highly touted by those that have them, but I really do not like it's aesthetics. I was constantly hooking stuff on the stock when I was pulling the gun out of the truck, duffle bag, etc... when it was folded. Strangely I never fired a round with that stock attached. It was loaned to me with the promise that "this is the ultimate folding stock". I took it on vacation without having time to test shoot it and came back saying, "No, it catches on everything." Fine for people who are organized to carry firearms, like police of course
. But like I said, quite a lot of the time, mine is in a duffle bag, or behind the seat with a lot of other shtuff.
The ATI side folder is crap. So is the forearm replacement that comes with it. The stock itself kinks at the joint when you shoot it, and the replacement forearm is not fibreglass reinforced plastic, it's made out of the same kind of cheap plastic that they used to make GI Joes with. It's crap.
The Butler Creek side folder is - like the Choate - solid, but awkward and inconvenient. I did not use it much or long. I had replaced the forearm with a shorter one (for use with side folders) at the time and did not like the stroke or handling. I got rid of both in short order.
To be utterly honest with you, after all of that, the stock that I have on my shottie now is: A normal fixed stock in synthetic. I shortened the gun by switching to a 12.5" barrel from an 18" and was much more satisfied with that than I was with any of the folding stocks I have tried. I will likely by a Knoxx SpecOps stock next year and try that too though.
