I don't think Harbeth follows the Harman philosophy in all respects, actually. The Harman/Toole approach is basically to emphasize flat and smooth frequency response in the "listening window" first, and second to prioritize smooth dispersion off-axis. I perceive Harbeth as being more in a kind of British tradition, influenced by the BBC, where the emphasis is often on the direct sound on-axis, and you then take whatever you can get when it comes to response off-axis. (this is a simplification of course, as several British manufacturers do things differently)
Most Harman speakers nowadays use some kind of waveguide, for example (shallow or deep), whereas Harbeth doesn't use waveguides. I haven't seen any explanation from Shaw as to why he doesn't use waveguides, but I assume that he doesn't think it's worth the trade-off (narrower directivity in parts of the spectrum, and possibly HOMs or resonances). Another distinctive feature of Harbeth, which several other British manufacturers also use, is the use of thin cabinets, which allegedly brings the cabinet resonances down to such a low frequency that they don't matter anymore. Harman speakers, on the other hand, usually follow the approach of using rigid cabinets which try to get rid of resonance altogether. I also think many British manufacturers - both Harbeth and ATC and others - also put more emphasis on the actual quality of the drivers, compared to speakers made "the Harman way", where it's more a question of implementing the drivers - cheap or expensive - in a way that achieves flat frequency response.
I'm personally using a pair of speakers made in the same tradition at the moment, the active DM10s from British AVI, and I enjoy them very much. Design philosphy is focused on the direct sound, a thin vented cabinet with flat baffle which gets resonances down in frequency, focus on getting the best drivers possible, very steep crossovers which free the drivers from distortion and break-up modes but doesn't create even dispersion. So the design is not driven by directivity first and foremost. This goes against many of the current "best practices" in speaker design, I know that. Still, the direct sound in the near- or mid-field is nothing but phenomenal to my subjective airs when aided by subwoofers. But they do suffer somewhat if listened to in the far-field, due to the lack of directivity control. So I think a case can be made for this particular British school of thought in loudspeaker design - prioritize the on-axis, no waveguides etc - in certain use-cases at least. (I wouldn't choose my AVIs for far-field listening or wide "social" listening).
As to European speakers which are made according to the Harman/Toole philosophy, I think there are no speakers that incarnate it more than the Dutch & Dutch 8C. These speakers were basically designed using dr. Toole's book as the bible: Smooth directivity, trying to avoid reflections from the front wall behind the speakers, but otherwise allow room interaction, deep bass extension, and more. There are others also - British (yes) Kef has focused on even directivity for almost 50 years, way longer than Harman, the Finnish Gradient speakers, and many of the European pro manufacturers do the same (Genelec, Neumann, and others).
But it's important to remember that Toole's research also contains other things which are sometimes forgotten in these discussions. His blind tests often showed that people like wide directivity in speakers. But in several Harman designs from recent years this has not been the determining factor in the design of the speakers (which necessitates the use of smaller drivers from the mid and up, as was done in the Primus 362/363 for example). The emphasis has rather been on achieving even directivity through the use of waveguides, which usually narrows directivity below 6 khz or so, even though it can widen directivity in the highest frequencies.
As for me, I'm currently on the lookout for a pair of used Infinity Primus 362 (from Harman) for our living room. So yeah, the Harman/Toole approach definitely has its virtues. But am I going to sell my active AVIs which are used near-field in the man cave? No way, until death do us part!
