Is it as good as the first film, better, worse? The answer is: I DON'T KNOW!!! (cue hysterical sobbing).
One things for certain is that it's very good. It's funny, heart-felt; stylistically it's a triumph; musically it's exceptional The action scenes are breathtaking, the acting superb, the animation excellent. It tells a fun story. Its use of Jack-Jack, a character who could have been irritating, works brilliantly, it ticks all the right superhero/60s spy movie boxes.
It doesn't have a volcano, and that lack of such an exceptional set-piece is probably one of the areas where the original movie wins outright.
But it does have a baby fighting a raccoon, and that might make up for the missing volcano.