Someone said to me today, "I've never heard a mouse fart." We were talking about moderators and running tests to actually measure the performance of our devices. You know the whole "mouse fart" and "virtually silent" thing is like "one hole at 25 yards"... hyperbole. The quietest projectile launcher I have ever heard was a 9mm sig shooting subsonics with a moderator. All you could hear was the slide. Go rack the slide on a semi-auto pistol. There AIN'T NO SUCH THING AS "mouse fart" quiet.
Most spring rifles are quieter without a moderator than most PCP rifles are WITH a moderator ... and that is
proven for me by testing not by hearing what I wanted to hear. That's a fact. Lot of times we think a gun (particularly a springer) is louder than it is because the noise of the action is so much closer to our ears than the noise of the muzzle blast. You might THINK, "what's 2 feet?" So I'll tell you. Two noises one at 3 inches from your ear and the other at 2 feet from your ear, the same absolute volume level. The one at 3 inches will sound like it is 18-24 decibels louder than the one at 24 inches. That is the MATH. Keep that in mind when making these comparisons.
That said, silence is fine but below some level it becomes irrelevant. If you are making more noise clumping about in the woods than your rifle makes when you shoot it, well then the performance of your moderator isn't really all that important.
Someone else said there are good reasons for choosing each option and he was right. The quietest AG I own is my D430 tuned by John in PA. It isn't really powerful at 12 fpe but it will compete with the average PCP at 30 yards (well it did on the 30 yard challenge). It will make meat as well as any PCP out there when it comes to SMALL game. But in my case, as I said elsewhere, my AGs would be trading material and I would rely upon more traditional means (trapping) to get my game. I am sure Manny knows a bit about trapping as well. The easiest way to get food in the wild is to trap it BECAUSE it frees you up to do other things you might need to do. The trapper multitasks and gets much more efficient use out of his time.
So, I guess if you aren't going to use your AGs for hunting you don't need them at all unless you are foolish enough to think you are going to use them for self-defense. Now that MIGHT work, one on one in a deep woods or jungle setting, but that AINT gonna work in the desert or in any environment where you are static. So that's strike two against ANY AG for scenarios where rule of law isn't reliable.
When talking about these ideas it is good to remember that YOU might be able to make that PCP run for as much as a few years but eventually it is going to fail just like any other piece of kit and you aren't going to replace it. The WORST possible scenario is you carrying your BB gun and turning a corner to face a group of folks intent upon taking it from you or worse. The second worst is you hunkered down in your hut, house, cave, whatever and something like a Cougar, Bear, Jaguar, or pack of feral dogs decides you look like dinner or worse that bunch of folks you managed to dodge at that corner this afternoon, saw you and has followed you home because you look like dinner
.... At that point you're going to wish you had a sharp stick over that paper weight.
Would I keep an AG? absolutely, damn fine tool for certain things... "Here son, take this and go kill a couple of rabbits. Be back an hour before dark and stay on this side of the creek."
The rest of this is just chest thumping.
EDIT: No insult intended.