Performance of Firefox 1.06bpre improved significantly with firmware 2.2009.51-1, to almost (but not quite) MicroB levels.

However this 1.0rc1 release is a step backwards in terms of stability, and it's integration with the virtual keyboard is woeful (so bad I wonder if anyone even bothered testing with the keyboard closed). Accessing bookmarks when the hardware keyboard is closed is a complete pain.

Performance of the rc1 has improved slightly over 1.0b6pre, but this is nowhere near ready for release.

Other than plugins/addons, I really can't see what this has going for it on the N900.