I know many of you use the www-client/chromium and chromium-bin packages, even the -9999 version which updates directly from the upstream's svn. I'm sure you'd like them to be the best we can do.
I have created a project page for Chromium packages maintenance for that reason. One of the goals is to build a community of users helping with the packaging efforts and providing valuable feedback.
If you are interested, please take a look at the link above. It contains useful bug queries, especially for ones we need more help with (Herd Testers Help Wanted). Frequently, a comment from another person confirming the same problem (with emerge --info and build log if applicable) would make diagnosing the issues easier and faster. And if you can provide some additional info, or a detailed analysis what is wrong and how to fix it, that's even better.