Its a matter of preference. EVERYONE doesn't like them, but a majority of the designer on the net like them, thus other people make it. There are still many designer that make the old clean way like Deve and NJ29. There are also those who make those grunge sigs using brushes which are considered n00bish compared to the ones NJNets makes because what the new style is, it is harder to make than the old one.
The style is more like abstract, and lighting becomes a bigger factor in designing.