Is the cabinet level with the ceiling or recessed?
Flat top is good. The cupboard is flush with the ceiling. If the wardrobe is placed against the wall, there will be a gap between the wardrobe and the wall. If you don't do it well, the gap here will be ugly and easy to scale. When making a wardrobe, the flatness of the wall is not good. After the wardrobe is installed, this seam will be uneven, different in width and ugliness.