A classic, but also primitive adventure.
The good: There is a lot to like about this adventure. The use of events, encounters and dungeons give a nice variety. Also the adventure does a good job of making the characters feel like refugees one step ahead of advancing armies. Draconians are interesting monsters.
The bad: The dragon antagonist is overpowered and can easily wipe out the whole party if the DM plays fairly (even taking into account the party having a one hit kill artifact in there possession).
Lack of variety in monsters. The draconians make sense being the featured monster and the bulk of the invading armies, but spectral minions are incredibly overused especially for a fairly uninteresting monster.
The adventure also tries its best to force people to use the pregenerated characters and offers no support to people who would rather create there own characters.
Summary: This was a massive step up in adventure design when it came out 30 years ago, but compared to modern adventure design it is undeniably primitive. There is a lot of flavor and story that is more interesting then many modern adventures, but the nuts and bolts of the adventure are bad enough that even if you still ran 1st edition you would have to spend several hours "fixing" the adventure.
[3 of 5 Stars!]