Current or Previous Harbeth Owners…

Back in the 1990's I owned a pair of Harbeth HLP3ES bookshelf speakers with a matching pair of Harbeth passive subwoofers. Did not care for the subwoofers but I did like the HLP3ES, which was a very pleasant sounding speaker.  I do, however, prefer the sound of my 1980's KEF Reference Series 101 bookshelf speakers, which I find to be more involving.  I also owned a few pairs of Rogers LS3/5A's, another lovely British bookshelf speaker, as well as an original version of the Linn Kan. The KEF 101's still sound best to me.  

Rockport of course! 

I have owned Super HL5 Plus, and currently have Compact 7-ES3 30th Anniversary and P3ESR SE.  A good friend had the 40.2 and sold them.  I was baffled when he did, they were amazing.

There's always something "better", but at their price point, Harbeths are hard to beat.  It's going to come down to what you prefer. 

I replaced the Super HL5 Plus with KEF Reference 1.  The KEFs are a little more detailed and dynamic, without being bright.  With a little more laid back electronics, I may have liked the Harbeths better.  I have also owned Stirling LS 3/6, which are very similar to the Super HL5 and were close to, but not quite as good as the Super HL5. 

Even though they are a "lower" model than the Super HL5, I liked the Compact 7-ES3 30th Anniversary even more.  They seemed more cohesive and had less tendency to be bright.  

The P3ESR are amazing, but really made for a small room or near field listening.  I absolutely love mine and while I never say never about swapping out any component, it's unlikely they will ever leave.

The 40.2 are simply amazing - the tone, timbre, and texture of the music along with their ability to fill a room make them really special.  Imaging is great and they can create a very large soundstage.

My pre purchase comparison was The Revel Line of Speakers and Harbeth. I overwhelmingly preferred the Harbeth sound and presentation. Within that group I compared the Super5+, the M30 and the C7ES-XD. I was able to hear them with equipment similar to or the same as mine. For me the C7ES was the clear winner. The best soundstage and clarity. In comparison the M30 was too dark and lacked openness although it was quite accurate and the Super5 was a little too bright and while it offered slightly more low end I still preferred the openness of the C7. I listen to Classical, Jazz , Pop. The C7 blends perfectly with my Accuphase Amp, Aurrender Streamer and MSB DAC all of which have a similar warm, and open sound with excellent clarity.

For me the C7ES was the clear winner.

I think the Compact 7 is an overlooked hidden gem.  I agree with your assessment about it being the "Goldilocks" speaker in their lineup.