The more I work with this film and process, the more it proves to have advantages beyond just being an interesting experiment.
I shot a roll of XP2 after shooting some Velvia 50, and long story short, the first four frames were 3 stops over exposed. Figuring those were a total loss, I reset the shutter speed to overexpose by one stop, as my previous tests had indicated. Half a roll is better than none.
After developing I was amazed at how forgiving this film is to over exposure. Not only did 3 stops not ruin the image, they turned out great. Obviously they were a lighter than the one stop overexposure, but I have never seen any other slide film that would accommodate that sort of extreme. The two stops difference on the XP2 looked better than a half stop difference on the Velvia.
The other thing that stands out is the dynamic range. As you can see from the shadows in the image below, this is shot into the sun, using the tree's shadow to shield the lens. The sun was above and behind the fountain, making the white spray essentially specular. So between that and the shadows on the grass and the tree trunks, this image had a good five stops of range (at least). On both ends of that range, the brightest highlights and the darkest shadows are perfectly exposed. One advantage of Ektachrome was its ability to capture an extended range; but at its best, it was nowhere near as good as this. You would be hard pressed to get a print that can produce this kind of range so accurately. Good contrast and extended range are very conflicting requirements for any image.
The "scan" below is just a hand held d!&!+@l shot. I did some correcting to make it look close to the original, but nothing fancy. As you can see from the border, the film wasn't even laying flat.