I think Dagobah is one of the best sets ever designed for a film. Bespin is not necessarily a bad set than it is a trendy set--it reflects certain late 70's design aesthetics. The ROTJ sets are about as good as any fantasy film from that time period and hold up today. Personally the phoniest sets are in the PT--i mean look at the Trade Federation control bridge--the plastic-coated paint makes the walls and detailing look exactly like what it is.