It's very situational. I built a rich SPA with lots of animations a few years ago and sometimes I would have no issues and other times animations would chug on one or two browsers. I haven't done animation work in the past couple of years but I used GSAP for that product and it was great. It's very tough to navigate the animation world because fades work great in context A on FireFox but work like crap in the same context on Safari. You might see the opposite on context B with a different animation.

Hopefully in a few more years we will see better and more consistent performance across all browsers, but we aren't quite there yet with CSS