I found and purchased this initially as a substitution for Chapter 2 of Waterdeep: Dragon Heist. It's a terrific dungeon, with some very clever and unique concepts. In particular, the Crystalite room has a very unique gimmick, and leaves a lot of leeway for out-of-the-box thinking on the part of PCs. While this could be seen as just a series of different rooms, there is actually quite a bit of interaction between rooms, which binds everything together neatly.
All that being said, there are some problems with Blue Alley. For one thing, there were several times in running this that I or my players found plot holes or inconsistencies in the descriptions and features of the various rooms and items. Nothing game breaking, but enough that it caused delays as I had to search through the book to find out if there was an answer or if this was a case of overlooked information. I concede that not everything can be accounted for when writing an adventure, but these were all faily common sense things that any average player would question or ask, nothing that would be considered unexpected. Basically it needs another read-through and editing session to smooth out some of the wrinkles.
Secondly, I found the difficulty chart to be significantly off. As I said, I ran this as a replaceent for Chapter 2 of Dragon Heist, with 4 PCs. When they reached the point where Blue Alley would start, they were at 2nd level, and according to the difficulty table this would make them "Weak". Accordingly, I bumped them to level 3 (without this bump, they would have reached level 3 about halfway through Blue Alley), as I wanted this to be challenging but not deadly. Ultimately though, I should have left them at level 2, as they sailed through Blue Alley with little difficulty. They took a while to complete it, as they are an extremely thorough and meticulous group, but they never really faced any true danger. To be fair, one of them is an Aarakocra, which essentially nullified the hanging platform room, but this one room wasn't enough to shift the balance that far.
In conclusion, this was a great adventure that I was very happy with, and will definitely use again for other groups. It just needs a little more attention to detail to tuly excel.