Well, I'm going to give this a five star, since previous posters have been grossly cruel in teheir reviews.
Because of the old reviews, I bought this through Amazon. And, there's actually some pretty good plot links by Asmodeus, as he draws various devil lords to do his doings, but the players don't seem to have much control over that outcome.
That said, this is really a big hack and slash festival. And, that isn't necessarily a bad thing. All depends on the style of our players and on you.
The thrust of this adventure is to put the group on a cool devil ship with a devil crew, which the wizard lends to the group, as they go looking for a temple that has been displaced. Mind you, this is a good temple.
Asmodeus has a whole plan here but he never shows up. Another devil lord does though and you get to fight him. As you can imagine, this is quite bloody. Pit fiends are numerous and the lesser devils are all over the place. This is going to be a bloodbath either way and hopefully it's the devils biting it and not the players.
Would recommend this for the right group of gamers who want mostly hack and slash. If you want more RPGing or negotiations or problem solving, you will need to add/subtract various points into/out of the module. That's what I'm doing.
BTW, there's some really interesting info on the hells here as well as what spells and items don't work/work poorly on the planes of hell.
If you want an adventure in hell that has more mystery to it, more opportunities to roleplay and far less combat (yet still some deadly combat), look for THE FIRES OF DIS which I also wrote a review about.