Well, speaking post-upgrade...I think MT 4.2 is broken - at least from an upgrade standpoint. Clean installs seem to be a non-issue. Having upgraded from 4.12 to 4.2, menus in Firefox are now broken (they still work in IE) and there's some formatting issues I'm seeing in the 'Tools -> Plugins' page where the boxes rendered around the plugin name are not spaced right on the last 2 plugins, with no padding between it and the main box. Also, it doesn't look like rolling back to my previous install is possible - I tried it and was greated by an 'Invalid Login' error message. Argh.
Oh, and I guess it also bears mentioning that SixApart has removed the download from their site, with a lovely 404 error in its place. I guess that, perhaps, is the most telling of all. Does this mean the release is being pushed back?
UPDATE 18:55 EST: It looks like the download page is back. No telling what the issue was...
I do not have any problems downloading. It IS still there.