I shot a Glock 19 yesterday with a Silencerco Omega9K and was very impressed. Also shot two MKE Z5Ps side by side with an SWR Trident on one and the Omega 9K on the other. The Omega 9K sounded slightly quieter.
Not scientific or exhaustive I know, but if buying a compact 9 right now I would get an Omega 9 K.