Personally, I like the breakfast at Top’s - if characters are a priority - the dinner is above average at both in terms of quality. I don’t get worked up about pre-fixe at CG - sometimes it’s nice to have the choices narrowed.
I don’t prioritize or look for fine dining at Disney anyway - so it’s more for the experience - which I think during fireworks - CG would definitely be the winner. So for me, since I can get Top’s dinner fare just about anywhere else (and CG for that matter) - the show at CG wins for me.