few more points to add to the discussion, given recent comments
1. i don’t think there should be any exclusive emphasis on harbeths... it is just that it is the topic of this thread, where the op specifically asked what is so special about harbeths... indeed there are many brands of speakers, past and current who uphold the bbc heritage and design philosophy
2. spendor’s 7 and 9 series couldn’t sound more different than their brethren classic series of bbc lineage... the modern floorstanding spendors are designed and voiced to compete with focals, revels, magicos, that ilk... it is a purposeful bifurcated product strategy to cover both bases, sonically and aethestically, one is for a modern sound modern look (for better or worse), the other is, well, ’classic’...
3. vandy’s certainly belong in the same conversation with the fine bbc heritage speakers like harbeths in that they offer a non-hifi, easeful, non-hyper-detailed sound... and as you would expect, vandy’s also often engender the same criticisms (lack of ’super-clarity’, slam, sound ’dead’, blah blah) from those wanting a more overtly hifi presentation... but make no mistake -- to make vandy’s sound right, they need the right, hella strong and sweet amp, even moreso than harbeths... this to such a degree that upper end vandy’s build in the bass amp into the speakers to take a load off...
4. agree that new harbeths are now darned expensive, too expensive, and there are many alternatives out there, many of which are very fine indeed, if different in how they present music, especially vocals... but really good stuff is never cheap... and yet cost and value are in the eye of each beholder and wallet
5. finally, i am currently lucky to have both the spendor classic series sp100 r2 and the harbeth mon 40.3xd... each also presents music differently, in numerous subtle ways, subtle tonal differences, while maintaining many common, endearing attributes such as an utterly natural sound with excellent transparency, full bass, easeful, effortless presentation (and the ability play loudly without strain if so desired)...