Some particular problems you should be aware of:
- Apple apparently has made it so that many of those third party lightning connector cables will not work with the new iPhones.
- iOS 7 has a serious lock screen bug (Apple is working on a fix).
- A large percentage of iOS 7 users are reporting battery issues.
There are many more, I strongly recommend waiting to upgrade.
I think it is fair to say that this is Apple's poorest iPhone "upgrade" ever.
If you are not convinced by all the stories below that iOS 7 is a catastrophe, try looking at Twiiter:
Twitter / Search - @ios7
WARNING: you will see some very graphic language used!
First I include one article from yesterday evening:
Remember that the links below represent less than a third of the negative English-language press generated about the iOS 7 and iPhone 5C/S in a 4 hour period sampled about 1/2 hour before writing this post...
iOS 7 Bug Allows Thieves to Bypass Your Lock Screen to Access Photos
London Apple cultists dismiss the iPhone 5C - Regents Street queue not interested, survey says | TechEye
Apple holds back iPhone 5S from suppliers - Suppliers grumble at Apple crumble | TechEye
Amid Shortages, iPhone 5S and iPhone 5C Reach Stores Today – ReadWrite
Wall Street watching early iPhone sales nervously
Why Apple Investors Should Worry - Forbes
Disable Annoying Features On iOS 7
20 public responses to iOS 7; poor battery, childish design and more | Mobile content industry news | Mobile Entertainment
Look At All The Bugs And Glitches Tumblr Users Have Found In iOS 7, Apple's New iPhone Software (AAPL) - Connecticut Post
iOS 7: Readers have their say on the update of the operating system - Telegraph
DailyTech - IOS 7 Lockscreen Bug Allows Anyone to Sidestep Passcode, Access Photos/Email
Apple iOS7's Biggest Design Problem: A Critique by Richard Turley - Businessweek
Little Boy Feels Your Pain, Has Meltdown Over iOS 7 [VIDEO]
Welp. That's that. Miley Cyrus hates iOS 7. | VatorNews
Apple Tries to Prevent Fallout After iOS 7 | InvestorPlace
iOS 7 Causes 4-Year-Old Boy To Cry Uncontrollably | Ubergizmo
Users complain about iOS7 upgrade | IT World Canada Syndicated
iOS7: What iPhone users don't like about it - Your Community
Apple iOS 7 flaws, oddities and mistakes | ZDNet
iOS 7: 5 worst features | The Full Signal
iOS 7 launch hit by performance and security issues | The latest news from the Computer and IT Industry | PC Retail
Tekrieg | iOS 7 Update Annihilates iPhone 5 Battery Life!
Apple Blocks Third-party Lightning Cables with iOS 7 | Geeky Gadgets
Apple IOS7: iOS 7 blocking Fake/Not Original Charging cables (and how to get around it) | 360Nobs.com