Been there last week, funny to find a "via ferrata" such far away from the alps. Our daughter had some fun and angrily refused any kind of belay ;-)
One should stress that the walking / hiking parts prevail. The upper part of the trail is mainly ment to bring you to the restaurants on the hillside; from sportive point of view you better turn around after the last ladders (part "3" in the picture http://www.klettersteig.de/Klettersteige/Bilder/1452-2.jpg ).
Compared with the Calmont nearby the "Rheinkletterstieg" offers more scrambling, more traffic noise but less (!) exposure IMHO.
Testing this route with Eddie.