Please tell me whether it is better to build a building or a bungalow on the hill in the countryside?

Two-story good, in fact, two-story? The first is a little more space, you should not use so much space, right? The second thing is, two floors are not so hot in the summer! I think the plains to build a building, built on the mountain (more mountains, more earthquakes, square is easy to escape), and square is more convenient than the building.

The following dedication 10X10 2-story self-built house design plan:

Think good if you add some points plus attention on it!