This is the best piece of work released by the D&D crew in the last 4 years. only the Neverwinter material comes close.
you get a great villian, a great map. decent descriptions and the ability to enter from multiple directions. you could have multiple parties play sequentially or together.
I ran this adventure several times last year - we eventually ran through all the areas of the map. it was a lot of fun for both experienced as well as new players.
at the end you have the possibility of a returning villian with whom to harrass your players for a long time (liches are notoriously hard to truly kill)
5 stars - I would give it 6 if such a rating was available.