Notch got it mixed up. He just released them in reverse. Alpha was great, and Beta crashed like mad for me no matter what. This had better get fixed soon. The game is not even playable for me in the current state.
I have another PC with an unupdated Minecraft. How could I keep it from updating? I hate Beta so much that not even all the swearing in the English language can scratch the surface.
I have another PC with an unupdated Minecraft. How could I keep it from updating?
Backup the bin folder inside of .minecraft, then update minecraft. After it finishes, close minecraft and overwrite all of the old files EXCEPT the file called "version". That file is what tells the launcher what version you have, and updating it alone will trick the launcher into not updating the other files.