Underground is a mix of both, even in the plains and deserts most homes and stuff are carved into the earth. But basically yea I guess artistically I think I have you beat hands down, the dwarves have been in this mountains forever and have carved out some really good looking stuff. Militaristic I think I edge you out as the dwarves are pure defensive, and have had centuries to perfect their defenses. Lava and spike traps are common, and there are many areas for ranged units to rain death both inside and out of the mountains. Either way, the main thing about the dwarves is that, in their current state. They may not be able to lay siege to another nation, but they are one very, very, VERY tough nut to crack even for the most powerful armies.