Some reviews on the PZero Nero. People generally seem pleased enough. The 4th review down is from an Ibiza owner - didn't rate them at all! I can't read Spanish though.
http://www.tyretest.com/pkw_sommerreifen/pirelli/p_zero_nero/index.html
http://www.tyretest.com/pkw_sommerreifen/pirelli/p_zero_nero/index.html