I wasn't intending to go for iOS6, but though about plugging in getting the latest 5.1 on there and undo the jailbreak. When offered iOS6, I thought I'd give it a try.
This is just on an iPhone 4. Wifi stopped working straight away, with the attempted login of the Apple page. I did find a suggested fix to set http proxy to Auto,with blank fields,and it has been fine after that. Of course, that won't work if you need an actual proxy.
There's really not a lot different. A do not disturb option. Some pointless apps installed for me. Describing the maps as poor is being kind. Town names are generally not available because they are in the wrong place. Redhill is called Reigate. Leatherhead is called Oxshott. All the suburbs in south London it can't be bothered with, apart from Addington.
The first time I spoke through bluetooth on the Zed it was very noisy, but it has behaved itself since. No reboots and battery life is still normal.