http://www.brianklug.org/2011/11/a-quick-analysis-of-exif-data-from-apples-iphone-4s-camera-samples/
From this analysis there doesn’t appear to be any personally identifying information captured in the EXIF data. That could change over time but at the time of the release of the 4s, no, there was no info that could be tied to an individual without knowing additional information.
Regarding the location data, in my experience, if the iPhone Location Services are off before you take the photo (but Location Services are enabled for the camera), then if you quickly turn on the camera and snap a photo, the location can be way off, because the phone hasn’t had time to get a position fix. Subsequent photos are more accurate, but GPS can be quite inaccurate if you are indoors. Many of the photos I’ve taken in my house appear to have been taken inside my neighbours’ houses or gardens, according to the EXIF data.