Both.
John Ritter was the heart of the show, but after he died, the show sort of shifted the focus on the others and was still just as good. It got a little crazier and funnier. I still recall the one episode after John died where all the lying and conspiring caused everyone's dirty secrets to clash and they all guarded the phone to keep each other off it. Everyone got busted for something or another and the scene ended with:
Cate: "CJ, what kind of bar was this?"
Bridget's Date (after seeing CJ's ID as a phony ID): "I'm looking for a sexy blonde named C.J."
CJ: "I NEVER SAW THAT MAN BEFORE IN MY LIFE!!!"
This crazy episode showed the show writers were still at the top of their game. The series should have lasted at least another season if but to let the cast have a real farewell episode. I'd like to have seen both Ed O'Neil return and David Faustino make a cameo.