I used to use iCab as my main browser because of its speed and features/configurability. I resorted to IE for pages that wouldn't open in other programs, and OmniWeb for Unicode pages.
Safari does Unicode (I can throw OmniWeb away), is compatible with all of the pages for which I used to resort to IE (probably won't need that anymore, but I'm not throwing it away yet), and is speedier than iCab. I'll miss a few features from iCab, but for now, Safari it is, unless I encounter any major problems.
Safari still needs some features (e.g. the ability to relocate the cache, autofill, the ability to stop Flash animations, better Cookie management, etc.) and has a few bugs. The bookmark interface is heading in the right direction, but isn't as intuitive as Apple touts (try adding a folder).
I will admit that I haven't tried Chimera in about 3 months. I loved tabbed browsing, but it crashed too much, lacked too many features, and didn't do Unicode well. I haven't had any crashes on Safari yet. To be fair, I'm going to give a recent Chimera build a try, but when Safari is done, I suspect that it will be my browser.