“Bach is an astronomer, discovering the most marvellous stars. Beethoven challenges the universe. I only try to express the soul and the heart of man.”
A great piece of music is beautiful regardless of how it is performed. Any prelude or fugue of Bach can be played at any tempo, with or without rhythmic nuances, and it will still be great music. That's how music should be written, so that no-one, no matter how philistine, can ruin it.
A bonus video from Stanford University. The music is J. Strauss II and the dancers are excellent:
The cartoon at the top is by Doug Savage.