Upgrade to 4.3?
"Battery Life
There have been some reports that iOS 4.3 may have be less efficient in terms of battery life on some devices, under some conditions. Apple has struggled with battery issues since the release of iOS 4.0—a problem exacerbated by the addition of Persistent Wi-Fi to iPod touch devices. Standby battery life appears to be particularly impacted by this, so users who do not charge their devices every night may wish to hold off on this update until there has been some time to see what the actual impact is on battery life. We’ll be taking a more detailed look at this over the next few days and will update this article with our findings once we’ve had time to test battery performance under iOS 4.3.
Performance
Performance under iOS 4.3 appears to be about the same as iOS 4.2, except for the specific areas we’ve already discussed earlier: Improved performance with JavaScript-heavy websites in Safari and sluggish performance with the new Home Sharing features. Beyond that, users shouldn’t expect a dramatic speed boost (or decrease) when updating to 4.3.
Update or Wait?
For the most part, iOS 4.3 seems like a relatively safe update in every regard except for the potential battery issues we’ve noted above, which may not impact all users. There is little here that would require a user to update their device to iOS 4.3 to fix any issues or provide support for any new devices, and most could safely remain on the prior iOS release. Many of the new features are compelling, but more cautious users may want to take a “wait-and-see” approach. It will take some time for features such as AirPlay video support to make it into updated third-party applications, and Home Sharing may not appeal to all users until some of the limitations we’ve noted are addressed, and Personal Hotspot is not necessarily available on all carriers and will require some users to sign up for an additional service. None of these are reasons not to update, however; only increased battery drain is currently on our radar as a possibly serious concern.
http://www.ilounge.com/index.php/articles/comments/instant-expert-secrets-featur es-of-ios-4.3/
I would recommend caution. Personally, since I moved to an Android phone with all of the capabilities of my iPod, the iPod has been sitting in a desk drawer and largely ignored. Apple's customer attitude clinched it for me.