I'm on 5.0.1b2. Works as advertised. Battery life on my iPhone 4 and iPad 2 has indeed improved over 5.0.
I'd imagine 5.0.1 will debut in conjunction with the new version of iTunes supporting iTunes Match.
Nice! I'm guessing your idea on when it comes out might be true, although I would think apple wouldn't want to publicize its mistake at the same time of a delayed release of Match.