I've unpaired and re-paired about 4 times in total and never had a issue with getting things working again. As mentioned previously just make sure you make an encrypted backup of your phone to your PC or Mac otherwise you will lose all your health data that is stored on the phone by the watch. The weather app still loses sync every couple of days though, requiring a power down of the phone and watch to get it working again. It did this before the jailbreak though so it's unrelated and not unusual for a first release of Apple software.