I have some opinions on this. I do a TON of animation.
First of all, CSS can natively handle the VAST majority of what you’ll need on a day to day basis. Transitions and keyframes are wonderful things. The animations look smooth and amazing because CSS does an awesome job of tweening or taking care of the “in-between” of an animation. I use a ton of transitions to subtly enhance user interactions. Little feedbacks here and there make a huge difference.
The only MAJOR limitation of CSS is the limited number of interactions that can trigger said animation. You’re pretty much stuck with :hover and :active. Well, that and support. A lot of older browsers don’t support newer stuff like transitions. That’s where JS/jQuery comes in. You can easily trigger any event with really any event (click, scroll, mouse movement, whatever). Sky is the limit.
If you want even MORE animation ability, I HIGHLY recommend Greensock or GSAP. It’s as fast as it gets and absolutely destroys jQuery on execution speed of animations (again, now we’re talking about NOT having CSS handle the tweening because there are some limitations. Drawing vectors comes to mind.)
Here is a link for Greensock.
Here is what it can do.
