The bottom line
IE8 is clearly nearly ready for release. RC1 is stable and fast, and it contains a full feature set, although there is still a bug or two -- for example, the fact that it wasn't able to display RSS feeds in the Address Bar as I typed URLs.
Although it's generally not a good idea to use release candidates for production machines, I've been using RC1 without any problems on one of mine. The usual caveats apply as with any prerelease software -- it's not yet finished and so should not be counted upon.
