In case you're wondering how that iOS 4.3 update is going to work out for you, WIRED has released results of benchmarks they performed using the gold master (release) version of the software.
What they found was that the update provides major improvements in Safari's ability to run JavaScript. iOS 4.3 uses the new Nitro JavaScript engine for JavaScript rendering, and WIRED's tests showed that Safari was able to pull a SunSpider time of 4340.1 ms compared to 10626.4 ms for iOS 4.2.1. That's over twice as fast!
The iOS 4.3 update is available right now in iTunes, so if you'd like to