The central premise of this module is to spend an entire adventure weakening a single creature that the party was probably easily capable of defeating in the first place. As originally written, most of the other combat encounters were more suitable for a mid or high Tier 2 party, and required significant upscaling to provide a challenge. The new version looks to be a significant improvement for many of the subencounters, but I don't think it goes far enough. Fortunately, it is easy enough to upscale - simply add more demons, and possibly replace the final encounter with one of the demon lords (suitably reflavored).

The module does a good job supporting the exploration and social pillars. There's a pretty cool dungeon to explore, and plenty of opportunities for roleplay.

This is much better than DDAL05-14, but suffers a lot of the same problems. There's more opportunity here to solve problems by talking instead of fighting, but if things do come to fighting a competently-played Tier 2 party could handle most of the combat. Fortunately, the theme of the adventure gives DMs a lot more wiggle-room to add whatever creatures they want to make combats interesting.

As a Tier 2 adventure, this would have been pretty good. As a tier 3 module, it's pretty disappointing. As others have said, the written combats provide somewhere between very little and no challenge to tier 3 characters, and the adventure plot makes no allowance for the fact that tier 3 characters have access to spells like Scrying and Teleport. Throwing out the written encounters is pretty much required, though this can be challenging to do while maintaining the theme. It's a shame, because the premise is actually pretty interesting.

From a player perspective, this module is one of the best AL opportunities you will ever get for "high-tier shenanigans." There are good opportunities for roleplay and exploration, and it finishes off with the single most epic encounter I've had a chance to play in 5e so far.

From a DM perspective, this adventure requires a lot of preparation. Again, be prepared to change things to deal with observed party power and don't rely solely on APL/party size guidelines - high level casters in 5e have a lot of ways to do the unexpected. That being said, this is a lot of fun from the DMs side of the table as well, and putting together a challenging and memorable experience for your players - which the module definitely gives you the tools to do - is very rewarding.

Overall a fun mod to run. This is a pretty combat-focused mod, but there's more opportunity for non-combat interaction than in some of the T3 mods we've seen. As the first AL T4 module, the adventure has to address both "Hey, we're in T4 now!" and "I haven't played this character in two years, how do I cast spells again?," and the first bit of the adventure does a pretty good job of that. Towards the end of this part, things break down a little, with a "final battle" than can be trivialized by a few spellcasters. For some parties - epecially spellcaster heavy ones - significantly beefing up the written combats will be required, while for "martial" parties the combats as written might be a time-consuming slog. Use the first half of the module to get a good idea of your player's power level (which might have very little to do with the APL/party size guidelines) and be prepared to change things on the fly. With a few changes, this is a really fun adventure to both play and run.