Glad to see some of you have also discovered Aguila "Colibri" (hummingbird). My experience has been that both regular and super are extremely accurate, for single hole shooting @ 30 feet or less with my Stevens Crackshot, using one of several interchangeable barrels I've built for it. Add an old Weaver B4 scope and you're in business.
Quiet? More so than an air rifle. I haven't tried it in my Win 52D or other match rifles yet, but I imagine you hear mostly the striker falling.
Power? At close range, from a 16" barrel, even the regular Colibri goes through 1/4" plywood like it was paper, but will not penetrate two layers.
I've stockpiled several bricks, in case Chuck Schumer says I can't buy any more. It should be an essential (and silent) part of anybody's bird feeder protection program. Expect no client complaints, and rarely any kicking or dancing, if selection of delivery point is correct.
In some 50 years of sampling CB and BB caps, U.S. and European, this is the only ammo I've used which had any accuracy at all. And it's super accurate. The Mexicans have got their priming quality control right.