One thing I love about it is how clear and bright the sounds all are. Synths come in and they're as light as air, they float over the brittle drums. And there's all this echo (I'm thinking of drexciya here perhaps) that adds to that feeling of spaciouss.
On the opposite end of the spectrum it feels totally constricted, all the sounds artificial and airless.
And also the emotional strangeness of electro. It sounds inhuman, so even when it has human emotion it feels processed into some other zone of existence.
You could make a strong argument that a good chunk of postpunk synth stuff fits into the electro mode via Numan.
Per droids comment above about electro evolving and permeating through music, it survived in the south and became bounce music, arguably even trap is an evolution of electro, right?
Yeah, IF Viewlexx, Murder Capital. The Hague was a major centre of electro back in the late 90's.