As much as I love CSS, I could never see myself using any of this technology because jQuery (and many other JS frameworks) can do this with less code, simpler syntax and more browser coverage.
See also: the Firmin plugin, which abstracts away CSS transitions with clean Javascript APIs: http://extralogical.net/projects/firmin/ (Alas, it does not yet do automatic jQuery fallback.)
Though I love jQuery.animate(), it just can't match the GPU-rendering speed on CSS3 transitions and animations. If you can afford the development time, it's absolutely worth it.