Superfetch simply fills all available system RAM with programs that Windows thinks you will be using. Once it has done that, to start another application it has to either write the loaded information to the swap file, or stomp over it. Stomping is faster, but it still requires more than a few context switches to get it out of memory.
Sure, if you never load anything that Superfetch has not already loaded, it will be faster. I have done a lot of testing with this and have never seen Superfetch benefit any game, at all. As you know Ack-Ack, games load an enormous amount of data. The faster that can be done, the better the game is going to run. Superfetch does not preload 'data'. It only preloads program and the data segment of said programs.
That article is bullocks about it being a "bad idea". It will not hurt anything to disable it, and is always worth trying. Vista is particularly stupid when it comes to Superfetch. It will merrily tie up a computer for 5 to 15 minutes, depending on the available memory (this is where more RAM can actually hurt you) preloading everything after a fresh boot.
There will always be someone who has bought into the Kool-aid and will find a why to make it look pretty and shiny. Anyone who actually knows what they are doing would simply tell a person to try it and make up your own mind. It really is not that hard to do.