I ran the revised version (v1.1 released 2018-05-07) in context of a post-Tomb Of Annihilation home game, with a couple of minor changes to fit our ongoing stoyline.
There arer some valid critiques here. It's great that the author responded to the first round with a nice revision; but, there's still a decent chance some groups will find this a little easy, and it's also pretty likely this will run longer than four hours. I'm comfortable with dynamically balancing encounters (quietly adding HP to a boss so it doesn't go down too fast) and maybe letting them feel badass with easy fights once in a while; and frankly, at tier 3, different party compositions can trivialize different kinds of threats but still hit hard roadblocks in odd places. So, you need to be ready to smartly adjust difficulty at this tier, in my opinion. I was also happy to stretch this into multiple sessions for a home game. So these issues weren't a problem for me, but it's good to be aware of them.
Without loyalty to a faction, you'll have to rely on the party's innate sense of good (closing a hole to the Abyss) or at least "playing along" to hook them.
Among all the Tier 3 modules in this storyline, this is definitely one of the better ones (perhaps the best) for exploration, with a dungeon that is sufficiently complex to allow different approaches. As others have said, the number of combats will satisfy the bloodthirsty. Roleplay is a little lighter; although there are creatures to interact with, they don't have a lot of depth.
Confronting a dragon, fighting a number of demons, and concluding with a battle that invokes the iconic Balrog at the bridge in Khazad Dum, this is a pretty iconic D&D experience. It might not mean much to the jaded DM or player who views everything in terms of wargaming and challenge levels; but if you really play up the atmosphere, many players should enjoy getting swept away in a fun stereotypical adventure.
[4 of 5 Stars!]