After careful consideration, I have (got to choose nor the S600 ...) ultimately responsible for the z600 decided. Decisive was especially the extended battery life and - in my opinion - better handling of the z600. And I must say that I was at least as far as the battery life does not disappoint !! Had the camera 2 week vacation in use and have it at this time just 1 - times charged (shot at over 1000 pictures!) 2.
Since this is my first digital camera, however, I can draw little else comparisons. However, I am fully satisfied with my purchase and the camera can definitely recommend to all those who (especially at night) make no huge demands on the quality of the photos - perfectly adequate for "Otto-Normal-consumer", if not above average in this price-performance ratio!