The interior sets from the bridge, to the engine room, to the quarters were all great. Futuristic, yet still had a contemporary feel, that could have come straight out of an actual modern submarine or aircraft carrier.
The only nit I'll pick in regards to the interior set design, is the color palette. It was simply too dark for me. I know the real world reasons for it-selecting a color scheme that the previous series sets hadn't used in order to differentiate the ship and era from the others, but if this were 'real life', I wouldn't want to cram a crew onboard a ship for years on end, out in space, far from home, in an environment with such dark colors everywhere. Brightly painted walls, combined with environmental lighting, at least in the corridors, crew quarters, and common areas would be mandatory. Visits to Sick bay were a welcome relief in many an episode. It's brightly lit and the walls weren't so dark. Really, the best regular area shown on the ship.
I think I'd go nuts if I were ever stuck on Terak Nor...no wonder the Cardassians were so cranky.
One of the things the Bajorans should have done is give the place a face lift, to match their own sensibilities. No oppressively dark rooms and corridors. Turn the entire project into a reality show...Flip This Space Station.