Beware new software, especially a new operating system.
This is a tried and true pillar of Defensive Computing. Newly released software is inevitably buggy. In addition, operating system upgrades always have some compatibility issues with the applications that they host.
Anyone whose computing device is used for important tasks, should hold off installing new versions of their operating system. How long to wait, is a matter of opinion, but a couple of months is a good starting point. In the Windows world, common wisdom has long been to avoid a new OS release until the first service pack.
Waiting lets the OS vendor fix the most common bugs and gives other users time to come up with work-arounds for annoyances and less common problems. It gives application vendors time to get their house in order. By the time you jump in, there will be a ton of articles written by early adopters that can help with the inevitable questions and/or problems.
Waiting is a no-brainer.
When faced with updating my first generation iPad from iOS version 4 to 5, I waited until I was almost the last person on the Eastern seaboard to run the update. By then, I hoped, all the problems will have been found and dealt with. Sadly, that wasn't the case and the OS upgrade wiped out my iPad. And, I wasn't the only one either. Nonetheless, waiting was the Defensive Computing thing to do.
With iOS version 6, iPhone users are learning this lesson the hard way.
While Apple Maps got most of the headlines, there have been a number of issues in the new Apple OS.
1. Some early iOS 6 users could not connect to Wi-Fi networks. The problem turned out to be a missing web page on Apple's site (and, arguably, a poorly designed algorithm).
2. Some iPhone 4S phones and iPad 3 tablets that were upgraded to iOS 6 also started having trouble connecting to Wi-Fi networks - even networks that they were able to use on iOS 5.
3. Some iOS 5 devices had their Wi-Fi capability totally disabled when they upgraded to iOS 6.
4. Many iOS 6 users found themselves consuming mass quantities of 3G/4G data, even when their phone was connected to a Wi-Fi network. Apple issued a bug fix for Verizon customers, but others also claim to have the problem.
5. The Podcasts app downloads files unnecessarily. G.F. in The Economist, referring to himself as "Babbage", writes that
On a recent drive to Portland, Babbage was using Apple's Podcasts app, which he believed contained only downloaded audio files. During a rest stop, an e-mail from his mobile provider, AT&T, indicated that he had used up hundreds of megabytes while driving. The Podcasts app has a bug that leads to downloads of already retrieved files...
A bug is one thing, but feeling helpless is another. G.F. ended his blog with this gripe
Ultimately, users are responsible for looking after their own affairs. But then why does Apple not offer nor allow others to offer tools to help with self-monitoring, as is the case on the Android mobile platform? ... To charge for services is reasonable; to provide an ecosystem in which a customer has no way of knowing what they are being charged for what is not.
6. Some iPhone 5 users are experiencing very slow Wi-Fi speeds.
7. Battery life is a problem for some. BGR reports that "... iPhone 4 and 4S users who updated to iOS 6 are seeing their batteries drop from 100% fully charged to under 50% in a handful of hours – on standby." Macworld writes that "A significant contingent of iPhone users report that their iPhone’s battery depletes unusually fast under iOS 6."
8. The upgrade from iOS 5 to 6 wiped out the Music app for some users.
This is not to pick on Apple, I have made the same cautionary point here previously regarding Windows.
Finally, to illustrate that waiting is not just for bug fixes, consider Ted Landau's article The Trouble with iOS 6’s Passbook App at The Mac Observer. He was constantly confused by the user interface to the Passbook app in iOS 6 and summed it up with
I only wish the Passbook app did a better job of guiding users through the too-often cryptic and non-intuitive process of how it works. As it was, I almost gave up on the app before I had even one coupon loaded. This is not how Apple software is supposed to be.
Now that Landau fought through it, later Passbook users can benefit from his explanation.
As they say in Brooklyn, when it comes to new operating system releases, fuggedaboutit. At least for a while.
Update: October 9, 2012: During a break on the Sept. 30th edition of his radio show, The Tech Guy, Leo Laporte was asked by someone in the chatroom whether they should upgrade from iOS 5 to 6. After the obligatory comment on the maps, he noted that Siri was improved in iOS 6. Despite not being aware of any battery life issues, he nonetheless said there was no rush to upgrade. Specifically, he advised holding off until version 6.1 is released. See it here, it's 2 hours and 15 minutes into the show.
Update: October 11, 2012: Just ran across this. Walter Mossberg was asked about downgrading from iOS 6 back to iOS 5 by an Apple user unhappy with the new release.