There are a lot of fun skirmishes but it can quickly turn deadly if the GM utilizes the full potential of the Drows' darkness ability, at least if it is a party of character without darkvision. I would suggest using alternative light and darkness rules, not just for this but in general.
The problem with this adventure path is the lack of motivation player characters are handed. There seems to be no good reason for them to keep fighting a fight that they are not wanted in, nor seem to have much stake in. A little GM tinkering could probably solve this though.
Delirium's Tangle offers the player characters a well balanced array of challenges wrapped up in a classic dungeon setting, but with a rich enough atmosphere and background story to stand apart from the simple dungeon crawls. The combat challenges are varied and not too deadly. Furthermore, skill and ability use play a significant and well thought out part in the module.
Though the scenario features a solid backstory tied into current and past affairs of Absalom, the opportunity to share it with the player characters through roleplay or otherwise are not established in the core module, but is left up to the Game Master to explore. Bridging this gap could take this scenario from good to great. If you are GMing this module, check out some GM guide suggestions.