Given that the public release is usually bit-for-bit identical to the GM, except for the file name, why would you want an "upgrade" that changes nothing/zero/nada?
Apple has said that multi-touch gestures would not be included of the consumer release of iOS 4.3, but they are still present in the GM build. Those who enjoy the gestures might want to keep the GM build on their devices a little longer. I'm getting an iPad 2 on the 11th which should have 4.3 installed from the start, so unfortunately I'll loose that awesome feature.