Running into the same jank issue as well. Chrome 33, Macbook Pro i7 w/ 16gb RAM. While I'm not at 30fps (averaging in the 40s), there are definitely some frames being dropped.
could this be happening because of bad video drivers? gss uses css transforms to speed up rendering and a bad video driver can cause a browser to automatically switch down to software rendering of 3D transforms.
If GSS requires 3D acceleration to get good performance, I'd say that it needs some serious optimization somewhere.
Adding another slow layer is not really helping anything: by the time you have browser-C++-overhead + DOM overhead + JS interpretation/V8/SpiderMonkey overhead, adding another layer on top of this all is really not wanting to make me develop on this platform.
Runs a bit smoother in Firefox.