I find mine to be wonderfully accurate with my first choice ammo: QuickShok
I like the sights a lot, although I had to adjust mine all the way to the left like some of the M-1 carbine sights are.
My son has wanted my H&K .22 rifle for a decade. So I let him purchase it at a nice price and took his new Thompson in partial trade. We are both happy. I like the Thompson sights better. The barrel is a little longer for a little more speed from my QS. And it's as accurate as my H&K was with QS.
It has NOT been fail safe however. It had a few failures to chamber but they got less as I shot it. I've still only fired it about 300 rounds.