I also have an H&K/Umarex 416. I agree with Certifiable. I have put about 700 rounds through it so far without cleaning, and except for one or two misfires (that both had deep firing pin strikes and were ammo-related), it has not bobbled at all.
Compared to a S&W 15/22, the H&K is much closer in weight and feel to a real AR (while still being light and handy, about like a Colt SP-1). The manual of arms with the K&K is not exactly like a real AR...the bolt lock is cosmetic; not functional,(so is the forward assist) so you have to cycle the charging handle every time when loading and reloading. It has a decent trigger. Mine shoots groups of about 1 1/2" at 50 yards with a red dot, and I consider that excellent accuracy from a .22 AR.
It has quickly become one of my favorite rifles.