The tour through the main citadel is a little disappointing, its pretty short and covers very little of the supposed 7 miles of tunnels (probably about 200m!).
The Maginot line forts above the town are well worth a visit - but you'll need wheels. Also the main memorial - Douaumont is a stunning place.
The town is quite pleasant but the musak from the speakers along the riverside were enough to drive us mad...