The stand-alone Shadowed Keep is a classic and the Ashlar version feels polished and complete. It's unfortunate some of the original (and excellent) artwork didn't make the final cut, but the result is a glabrous old school aesthetic that puts corporate mannerists to shame. The new maps are gorgeous. Previously, each area of the keep was paired with relevant stat blocks and a compilation PDF was mercifully included. The new edition organizes everything into one bookmarked PDF (plus a version for mobile contraptions) with all encounter stats compiled at the very end. It likely comes down to preference, but this GM appreciates being able to quickly eye a nearby room's contents without changing pages. There are two minor issues worth noting, both of which are in the statistics appendix: Braal's domains are inconsistent with his Deities and Demons entry and Firean's abilities and equipment don't reflect her newfound faith. These are very minor and shouldn't impact gameplay, but attentive players familiar with the setting might bring it up (usually at the most impractical time).
The town of Dulwich now feels alive and vibrant: new locations, new nutters, adventure hooks aplenty, and East Gate's owner has finally crawled out of bed. I did notice a rogue copy-paste sitting in the Golden Skull, but what else should you expect from a den of thieves? Dulwich has the potential to rival Languard in opportunities should a group prove sufficiently nosy. Additional distractions can also be found in the nearby wilderness including a small settlement easily adapted to deal with nonstandard PCs that are otherwise accustomed to torch-and-pitchfork welcomes.
All in all, this is a massive improvement over the original work.