The premise of this adventure is cool. The set-up is cool. Then it becomes the Pen & Paper equivalent of a sewer level. The faction missions are uninspired, the combat is boring and the story goes nowhere. The background hinted at completely breaks down and gives way to one of the most boring crawls I've ever played. It was boring to read and my players did not enjoy this slugfest either.
The one PF scenario I don't want to run EVER again.

This adventure is a very straight forward, well paced delve and heavily combat orientated - what I think a crawl should be. In saying that, there is a need for a very well balanced party to succeed. I played 1-2 and was personally awed by the last act.

This is a great adventure for beginning characters or to introduce players to PFS/PFRPG. Particularly good for getting power players to realise that there is more than optimising characters and that they know all that there is to know in the game.

PS. I recently ran this scenario for my local players and they loved it! Highly recommend, particularly for hack and slashers.

A very generic "Fetch me my MacGuffin" dungeon crawl. Filled with deadly encounters and awful maps, this doesn't rank very high. The amount of roleplaying is close to naught. After the briefing it's just walking through a railroad under the city, seeing the wonderful sights of the sewers.

Last encounter is really some shafting. Most likely will make at least one player just leave the table to read a book or something, unless he/she is sadistic.

The adventure doesn't have a lot of RP built into in (though there is some if the PCs go out of their way to make it). On the other hand, the way the scenario is set up, it makes sense that the PCs will be fighting their way through this.

The entire time I ran this scenario, I felt the encounters were far too difficult for a group of characters of the first level to deal with and the adventure constantly throwing copious amounts of Cure spells in the form of a myriad magic items did little to offset the disproportionately powerful creatures the players were pitted against.
A specific encounter in which I felt that the players had little chance to survive without the DM's intervention:

The faction missions, although not brilliant, were a relative strong point of the Scenario. It was entertaining seeing the group's rogue shout in glee as he completed his faction's second task.
All in all, with some alteration this adventure shows great potential but if it is run "out of the box" you may encounter some problems. It is highly recommended to bring characters of the second level if playing the Tier 1-2 version.