In full the non-security changes are:
- Improves reliability of using HDR option for photos taken using the Lock Screen shortcut
- Addresses bugs that could prevent the new iPad from switching between 2G and 3G networks
- Fixes bugs that affected AirPlay video playback in some circumstances
- Improved reliability for syncing Safari bookmarks and Reading List
- Fixes an issue where ‘Unable to purchase’ alert could be displayed after successful purchase
No real biggie there, though if you were affected by a flip/flopping iPad HD then I guess you can expect dramatically better battery life now.
Security updates all revolve around flaws in Safari:
- A maliciously crafted website may be able to spoof the address in the location bar
- Visiting a maliciously crafted website may lead to a cross-site scripting attack
- Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution
That last one, on a locked down OS is a potentially big issue.
Recommend an update for all users but you could wait to see if there are any issues in the next 48hrs.
Seems ok on my iPad 1.