I think the Dark Council Chamber looks a lot cooler than the Jedi Hight Council Chamber.

I like DK better than Coruscant, because of the dark rainy dreary look about it, but that's about it.

They are both pretty poor.. Its like they got stripped of any details because they couldnt control the lag or something..

Despite favouring the Empire in general I think Coruscant is much more attractive than Dromund Kaas. Also rather more believable, Kaas City just seems too small and parochial to be the capital of a capital world, even with the skyline buildings making it look larger than it is. Coruscant on the other hand looks and feels like Coruscant.

 

As to the Jedi/DC chambers I think they are both very nice. I was impressed with how pretty Tython was actually, I was expecting it to be a bit of a let down after Korriban and Dromund Kaas.

I actually prefer the stripped down simple design of the imperial stuff, no gaudy decorations, everything is there that needs to be there with nothing else.

The best designs are the Rakata buildings on Belsavis, they have detail and a creepy kind of style, and are better than either the Jedi or the Sith buildings.

Considering the Sith are ancient they're buildings and cities are seriously modern looking. I'm gonna go with the Jedi because they have old temple style architecture, even on Coruscant which is such an industrial city they have an old looking temple. Much prefer the style.

Don't forget, the "nice" Jedi High Council Chamber is still in ruins on Coruscant. Think of what they have now like "temp quarters" while the rebuild the Temple One day it will look pretty again like we see in The Phantom Menace (well, until the Sith destroy it....again).