I have one and I really like it. I have only modified it by adding a strip of tape on the top of the barrel and by adding some swivel rings and a sling.

With a 3" slug and good shot placement at fairly close range, it's worked as a deer rifle for me. The .22 is, again at fairly close range, a decent small game gun.

I have not used it for bird, but I don't see why it would not be good.

I really like the simplicity of it, and I use it much more than the "novelty" gun that is my AR-7.