Mummy's Mask is great if you like a series of dungeons with a connecting plot. Not so great if you want something sandboxy.
Edit: Made a review that said exactly this.
That describes most if not all of the Adventure Paths though. If someone did not want that then AP's would not be the way to go.
This one is more so than others, IMO.
How is the connecting plot? Anything that one needs to watch out for? And twists that don't work or random NPCs that need help or omitted? I like the idea of the different adventuring groups so when the chaos of book 2 hits I plan on showing how those different groups handle the situation.
That describes most if not all of the Adventure Paths though. If someone did not want that then AP's would not be the way to go.
If this answer seems nonsensical, Its because I didn't really understand your question.