An interesting thread on EN World posed this question: What is the best introductory D&D adventure? Here is my answer:

Are you asking which is the best first adventure for a group of new players, or is the DM meant to be new as well?

Because I have substantially different answers depending on that.

For a new DM, stay far away from Keep on the Borderlands. I know that, in my youth, when I attempted to run it, I struggled to work out what to do with the Keep after the PCs arrived, and eventually said “to hell with it” and placed them directly in the Caves of Chaos, at which point it got good.

But that’s not what the adventure intends. In addition, much like The Village of Hommlet, Gygax doesn’t really understand how to construct a home base for a new DM to run. (Hommlet, at least has lots of good ideas in the base. Even if indifferently presented).

For a new DM, give me more structure and obvious lines of play.

• The Sunless Citadel
  
• The Lost Mine of Phandelver
  
• Against the Cult of Chaos (4E D&D Encounters adventure)
• Keep on the Shadowfell. (First half).

Keep on the Shadowfell is fascinating – I adore its early play with various missions interspersed with town encounters and growth. It falls apart in the second half. However, I suspect that run with 5E or another system that plays quickly, it would work a lot better. The “each encounter takes an hour” pacing of 4E hurt how Shadowfell worked significantly.

I also have a love for The Veiled Society, which despite a mostly linear plot, introduces both the players and DM to the joys of Urban play. (I reviewed it on my site, many years ago).

Now, as to an experienced DM? I’ll be running Hoard of the Dragon Queen or Keep on the Borderlands.

I am sure I’ve missed many excellent adventures in my answer – many of which I’ve even read and run. Those are just the ones that stay in my mind!