Harbeth is one of my favorite speaker brands.
Even so, I owned the Harbeth SuperHL5plus for a while (which sounded the most evenly balanced and neutral to my ears among the line), and sold it.
It did the things I love from Harbeth, beautiful with instrumental tone/timbre, and capturing a natural sense of vocals. But in shoot outs with my bigger Thiel 3.7s (which I was seeing if I could replace), I found the Thiels did much of what the Harbeth did but "better." By "better" I mean the Thiels also sounded fundamentally "right" with instrumental timbre/tone, but also sounded more clean, focused, precise and realistic. In comparison the Harbeth speakers had what I might call a "thickness" or "texture"...just barely there...that sort of connected all the sound, as if it was occurring between the instruments as well. This "thickness/texture" seemed to just clear up on the Thiels, giving the cleaner more precise sense of instruments performing in an acoustic space.
My hunch is that I was hearing the difference between the thin-walled design of the Harbeth vs the more "modern" approach of the Thiels which attempt to heavily brace to remove any box signature. So perhaps it was hearing just enough of those Harbeth walls "singing along" with the sound causing that slight texture connecting the sound. But I don't really know.
In any case, as much as I like the Thiels (and my other speakers) for most music, I still felt the Harbeths produced vocals with a more natural, human sound than the Thiels. Sometimes I miss that aspect of the Harbeths. I'd like them more as a second-system speaker.