First and foremost, this is a very beautifully done publication. It's one of the most professional publications that I've seen the Guild, with a great use of images and colour schemes to reflect themes and chapter content. And the cover image in particular is really top-notch.
It's also a very professional publication when it comes to the writing and editing. I also really enjoyed the purpose of this adventure, especially when it comes to Descent into Avernus - as that adventure lacks a hook that really makes characters care about Elturel. This adventure helps fill that gap.
I do wish the adventure was a bit longer - that it showed the journey to Baldur's Gate and how the characters might have gotten through the gate. But that's my own personal preference. And it would certainly make for a longer than 2-hour session. As is, the adventure is very nicely done.
Overall, when it comes to its writing, professional look and feel, and how carefully tied in it is to Descent into Avernus, I first thought that this might have been a Guild Adept product.
DM's Guild products are getting increasingly professional-looking, and its publications like this one - and others (e.g., Uncaged) - that have really spearheaded that trend.