Since there are only two kinds of reviews, either the “I loved it,” or the “I hated it,” kind, I figured I'd weigh in.
As a player: I loved it and I died.
Plot: Due to some time constraints, we were unable to unfurl the whole plot. It was obvious that, if we had both the time and the appropriate party, we'd have been able to really delve into what was going on with the individual characters.
Combats: We played high-tier, table of five, no adjustment, and not hard mode. The combats were rigorous, but appropriately challenging. After hearing people whine about easy combats for four seasons, the development team really ramped up the challenge rating, and it pays off. Making it through combats that were arduous is like a bragging right, and this truly satisfies. Moreover, it rewards the well-prepared party. At levels 7-11, being poorly or under-equipped is a personal problem; you've been given thousands of gold. If you spend it all on one weapon and one suit of armor (or whatever two-three high budget items you have) you're most likely not going to have what it takes to get through the scenario. It seems like these monsters were written with the splat-book and Ultimate Equipment items in mind, and I love it.
This scenario, through the course of its combats, had a foil for every kind of class. It wasn't a simultaneous foil for all the classes, but each encounter targeted a handful of class abilities and tried them. It was lovely.
As a GM: I'd happily run it many times.
Plot: GMs are exposed to more story then the players can even begin to consider. It's difficult to relay some of the back-story that helps really make the scenario come alive. I'm sure a more talented GM could work it in somehow with various clues and dropped hints, so it's not impossible. Understanding the context for the NPCs' actions helps to make them more convincing and multifaceted. They weren't the standard “I fight till death because that's my morale,” NPCs. That's not to say there weren't creatures with those stats, but knowing individual stories provides depth for the NPCs as they're run.
Combat: Just as challenging for the GM as it was for the players. The combats are mobile, and require an organized and prepared GM. Tracking monsters in large combats, as well as various saves and their DCs was a little heady, but nevertheless worthwhile. Running the monsters fairly can become cumbersome if the GM doesn't fully analyze the stat-blocks. Reading some of the reviews makes me question the GM more than it makes me question the veracity of the players' reviews. Plus, the scenario makes use of some atypical monsters, which is a fantastic switch from the low-tier goblins, the mid-tier giants, and the high-tier cleric-giant-monsters.
In short, if the players needed a GM for the table, I'd do all I can to run it. If the players needed another body, and the table (as well as the GM) looked trustworthy, I'd even strongly consider using a star to replay it. I don't build good characters at all, but being put through the wringer was quite fun!