Why do Harbeth speakers have such a cult following

The honest answer? Because Stereophile put them class A about 2-3 years ago. They blew up after that.

Harbeth's website describes their sound as "fresh'' and "natural'' which I think are very accurate adjectives.

To my ears the sound is also warm and relaxing, which should appeal to fans of most genres of music (except heavy metal/rap).

Other than sound quality I also think the appeal is that they do work well with a wide variety of amps - I recently listened to the Compact 7s driven by a modest setup costing about US$2k and the sound was captivating. The dealer actually emphasized the point to the several customers present that you don't need "crazy money'' to enjoy a Harbeth.

11-13-12: Bobheinatz
I owned the 5's and it always was enjoyable. It drew you into the music. Someday I will own a Harbeth again.

I also owned the 5's for a short time and Bob's comments sum up my feelings as well. It took me a few days to settle in with them, but after I did I enjoyed a lot of music.

Ditto Bobheinatz & Briangrarcom.

I am using a pair of P3ESR at the moment and they are great. Can't think of a better small speaker, fills the room perfectly, big sound, enough bass, punchy, with great balance and every record I play sound good, I don't know how it's possible, but it is what I hear! Easy to drive as well, and I can play very loud. In my opinion, in my room with my tube amp.