Quote - so I think if a renderengine is really significantly slower than another there must be a fatal error in the programming, or the settings are just too high by default :P

Please...

There are more than a handful of differences in rendering algorithms. Different renders have different sweet spots. For instance, Radiosity renders PREFER lower poly counts, as the initial calculations require each surface to be divided into patches before bouncing light around. For complex outdoor scenes like those generated by Vue, one could literally wait days for these calculations to finish. So, Vue has to provide a different way for managing outdoor Radiosity calculations-- one that is much different from the way, say-- Kerky or Brazil does it.

Blaming rendering speed as a function of 'fatal error in programming' is more than simplistic, it's just stupid.