$.animate and performs even better than CSS animations.
If you're looking for proof of concept, look no further than @legomushroom's CodePen demo which combines VelocityJS with a series of SVGs for a stunning result. Seriously, go check it out. The demo is smoother than any Flash video I've ever seen.
What exactly is VelocityJS? From the project page:
Velocity is a jQuery plugin that re-implements $.animate() to produce significantly greater performance (making Velocity also faster than CSS animation libraries) while including new features to improve UI animation workflow.
Since it's backwards compatible with jQuery's built-in animations functions, you can just swap out
$.velocity and instantly see faster and smoother animations. At only 9kb, it's worth including if you're doing any heavy animation in your web app.
These are exciting times for the web. I wonder how long it will take CSS animations to get up to speed with VelocityJS.