With the free release of the 5e Basic Rules, I'm looking for an adventure to introduce myself and my group to 5e (in the spirit of this question): we want to try the system before deciding if we'll invest resources in the edition.
- The adventure should be useable out of the box with only free Basic Rules publications. For example, I don't want to rely on Playtest content.
- The adventure should be free. Like I said, the point is to discover whether we want to dedicate our group's resources to 5e.
- It should showcase the strengths of 5e. Ideally it's a pitch for "why to play 5e" in adventure form, but at the very least it should be designed with 5e in mind. It's hard for me to imagine that a simple hack/update of a previous edition's adventure would be useful for selling my group on 5e.
- I'd prefer an official WotC publication, but third-party/homebrew adventures are fine--though answers suggesting non-WotC adventures will, I hope, provide some idea about their production quality in addition to how well they fit the above points.
- Starting at level 1 seems ideal, but I'm open to being convinced otherwise.
Some additional info about my group which might influence your recommendations: I expect between two and four experienced players in a face-to-face setting. We can dedicate perhaps three or four sessions of four or five hours each to the adventure.
As always, please remember that RPG recommendation questions have stricter-than-usual expectations about justifying why a particular recommendation is appropriate.