So, having now played and GM-ed this scenario, I honestly like it. It's a very well thought-out dungeon crawl that doesn't even need to be completed in a linear fashion (though completionist PCs will always map every square). The story's solid, stocked with memorable characters aside from the fairly flavorless end-boss. Faction missions are also pretty neat.
My only real gripe is the tiers. Tier 3-4 fights some pretty weak stuff (an orc with 6 hp among them), straight through to the end-boss, who still goes down pretty quickly if the party focuses fire. Really felt like tier 3-4 was basically "tier 1-2, but add two more of the wimpy dudes". However, going up to tier 6-7 looks pretty dang frightening.
(SPOILER: Lots of secret doors in this one. They substantially change the flow/difficulty of the whole mod.)
Overall, quite solid. Avoid running it at tier 3-4 if you can, it's boring with an even moderately-prepared party.
I ran this mod recently, and would recommend it. We suffered from an imbalanced party composition, with two level 1s, a level 3, and a level 4. For those of you playing along at home, that's tier 1-2, so the level 3 and 4 just trashed everything. Even if it weren't for that, the combat in this mod is pretty light, and most of it is optional in some way. That said, expect most parties to just rush in and bash heads.
Still, if you have a balanced party composition, this can be a solid mod for combat. And most of the RP opportunities are very solid, as long as you're willing to make your players act it out to some extent (my pet peeve: "Um... don't attack us, 22 for Diplomacy").
Faction missions for this are quality, and players need to actually read them in order to succeed. Almost had two players fail because they outright forgot half of their missions. Oh, also this mod has the potential to go *very* quickly. We finished in about two and a half hours.
As other reviews have stated, this is an incredibly linear and straightforward module. However, it is executed well, so that the party generally understands what is expected of them. There are a few fun puzzle-y encounters to balance out the combats, and there is actually a path through that doesn't involve destroying everything in your path.
The challenge was certainly present, although we had a 6-person table at the 3-4 tier. The two level 6 characters at the table dominated as would be expected, but I got a few hits in on them that got them properly worried at times. Players who already know about certain creatures hinted at in the mod title will be tempted to metagame even if they fail their knowledge checks, so be forewarned.
Overall it is brisk, it is fun, and it is well-executed. Would recommend.
