Despite a couple of drawbacks, the Empire Strikes Back is an immense amount of fun -- big and splashy and breathtaking in its display of cinematic genius by a huge group of marvelously talented people.
The Empire Strikes Back is no bland derivative. It has all the freshness and exuberance of an original. A marvellous space fantasy full of dazzling spectacle, exciting adventure, strange creatures and the mythic clash between good and evil.
To answer the big question first: Yes, The Empire Strikes Back is just as enjoyable as Star Wars. In fact, this is one sequel that defies tradition by being better than the original on several counts -- most of them technical, but a few dramatic.