I recommend still shoo goo'ing a bead around the edges of the servo. I have had those ears break at very inopportune times - including the A-main at a national level event on the 1st lap after getting hit in the 1st turn pile-up. Made for some interesting steering for 8 minutes.

After that particular incident I still use the tabs but also shoo goo around the case of the servo to the chassis.

Another method is to use double-sided tape to fasten the servo where you want it on the chassis and then do a bead of shoo-goo around the edge of the servo. It is a lot easier to remove the servo since all you do it peel the bead off and then release the servo from the double-sided tape.

-Rich