Personally, despite absolutely loving Gaudi’s whimsical buildings (there’s a delightful one with a roof that looks like a dragon curled up sleeping), and regarding Sagrada Familia as a tour-de-force of engineering (Gaudi used analogue computation done by hanging weighted sheets and looking at them in mirrors on the floor to find the optimal shape for his towers — you can’t build towers taller than that by stacking stones one on another without them being weaker), I think the building is uuugggly! (Especially on the outside — the columns like towering trees in the nave are quite nice.)
De gustibus non disputandem. I think it's beautiful, and fascinating. To me it's "gothic meets Buck Rogers".