I have have several .22 suppressors. I asked the dealer I bought them from to give me an update this past week as he got a bunch of new ones in. He had a half-dozen friends over and here's the response to an email I sent him:

"Just got done testing the new Silencerco Sparrow, new style AAC Prodigy, Spectre 2 and old Spectre.
The results by all in attendance was unanimous, buy a Spectre and stay away from the Sparrow. No one in attendance could tell a nickels difference in the Spectre 1 and 2. Pop on the Sparrow was ridiculous. AAC was good but not as good as either Spectre."

YMMV, I just found it interesting. I've never actually met this dealer but have bought a lot of stuff from him over the years, from 1911's to Sako TRG's and various suppressors from rimfire to .30