Most of the artifacts in Chrome Mobile stem from the fact that the latest stable version branches from Chrome 18 at which point the chrome compositor was in somewhat of a disastrous state (things are somewhat better in Chrome 20 and up). Chrome attempted/attempts to support transforms regardless of the underlying engine (be it OpenGL ES 2.0 or skia) and as result of this ended up implementing a lot of things that would be handled by OpenGL ES natively within Chrome itself, like backface culling, clipping, layer sorting, etc. Unfortunately, most of this math was wrong and as a result many things that use css3d transforms are a flickering disaster. Instead, I think they should have interfaced entirely through OpenGL ES and let a software implementation simulate it in the case of GPU-less hardware (which I think they've actually licensed and are already deploying in some later versions).
If you look at Safari, on the other hand, the only real major issue with 3d transforms is hit detection can sometimes be wonky, but this isn't something that OpenGL makes particularly easy anyway.
The ironic thing is that the stock Android browser is actually much better than Mobile Chrome, likely because it was written directly on top of OpenGL ES 2 from the start, whereas mobile chrome was actually a full port from the desktop. I haven't read much of the Android browser code though, so this is largely speculation.
