I have used several (may be 5-6) types of diffuser... Major issue was popping out when CO2 is on (turned off overnight and next morning when it is on, diffuser pops out).
Recently found out from evil bay, that they have this type diffuser with screw, and it never pops up when I use it.
No problem whatsoever, and no popups, no more dipping your entire arms to reconnect the tube with diffuser in the morning before go to work.