Thanks to everyone that helped test MozillaBuild 1.2rc1. A bug with cvs was found that makes cvs checkouts, checkins, and maybe other things fail in weird ways. RC1 was the first MozillaBuild to use cvs 1.11.22, for rc2 we've switched back to just plain 1.11. We've also added a couple of small enhancements. Notably, the font issue with ClearType/widescreens has been fixed. For a more complete list of what's in rc2 checkout the dependent bugs in bug 406085.
I should note that you must run start-msys*.bat "as administrator" on Vista.
Hopefully this next part will be unnecessary but if you do find any bugs please file them in mozilla.org:MozillaBuild.