This is not fact, just my observation, I think an air weight 9MM would be a handful. You really learn to like the weight of the 940 when you shoot it. S&W whole selling point as a backup for a 9MM SA went up in flames aginst combos like the Glock 17-26, the G26 killed the S&W 940. I have seen them at gun shows cheap but they are usually gone quick, usually priced like a .38/.357, people just don't know.
Well I assure you if I ever see one priced like a .38 I'll be sure to buy it in a heartbeat.