I certainly spend more time dealing with webkit quirks than IE quirks these days, thanks to the demise of IE6 and IE7.
So far, few of the visual 'bugs' I've encountered in webkit have been strictly 'non-standard'.
They pretty much ll fall into two categories:
- 1. Experimental, i.e. not yet standardised, CSS
- 2. CSS where the standards are silent on the precise method of implementing rendering, e.g. list markers.