Have ridden on Tourance and Tourance EXP.
EXP wears MUCH faster, but really sticks to the road, in wet or dry. Warms up fast but doesn't desintegrate. Ideal in any kind of weather, including colder weather. There's not much you can throw at these tyres that they won't hold, REALLY impressive ! Even tarstripes will not worry you too much. Handles terribly well, almost nervous. A real fun tyre.
The old Tourance wins on longevity, but doesn't handle as well (in comparison the GS has to be pushed into the curve), and although satisfying, it definitely has less grip. You cannot really blame this tyre for anything. Hence it's popularity.
At Cologne fair last year EXP was promoted as 'sportstyre', whereas old Tourance was dubbed 'tourer'. I think that's a spot-on description by Metzeler.
I guess it's the typical trade-off : longevity or grip.
I don't care too much about longevity, and have found the perfect tyre in EXP.