I have quite appreciated DMing this adventure.
The introductory part with the "drows are infesting the surface" theme was pretty intriguing, but the best part of it was the show-me-that-you're-worth-it brawl against the half-orc. I made it especially funny when the guy stripped naked and oiled himself up, something that the brawling player soon copied. A memorable experience for sure.
It was nice to see a more human side of the Red Plumes with Yestral (I made it so that a Red Plume initially made nasty comments against the party, but soon had his ear pinced by Yestral before going to his momma in tears).
I combined the derro (who were all screaming "DERRO, DERRO !") & kuo-toa fights to increase the tension and give an initial "oh darn" to the players.
The roleplay passage with Huum was a nice addition - pretty funny to roleplay a mind flayer.
I didn't think it was really appropriate for the final fight to have drows against the players, so I instead put some previously liberated drows with the players against a few combined encounters at once. Hard to manage, but rewarding for the players !
Overall, a quite enjoyable adventure, in my opinion.
[4 of 5 Stars!]