Are Harbeth the only warm and euphonic speakers in town ?

To me it would be in the smooth and warm category more so than "fast."  This is a bit of tricky dichotomy because some of the speakers that are characterized as fast, detailed, etc. give that impression by being a touch lean in the upper bass and lower midrange or have an upper midrange peak that emphasizes the initial attack of the voices and most instruments.  Good electrostatics actually don't have that kind of punchy initial attack that some characterize as "fast" and they have a natural "ease" and "poise" while not sounding sluggish.  In that sense, the Boxer is sort of like an electrostatic--the dynamics is not hyped up like some other "fast" sounding speakers (e.g., Zu speakers).

The warmest are Audio Note speakers.  Classic Spendors are also good warm speakers.  ProAcs, such as DB 3 are also nice, warm, speakers.  Nola standmounts should also be considered.  Any of the copies of BBC designs, such as Falcon speakers qualify as well.

Something like the Harbeth 30.2 and Falcon LS3/5A speakers are nice warm sounding speakers, but, for some reason the Boxers are overlooked and they are considerably cheaper than the likes of the Harbeth 30.2.  They certainly should be auditioned. 

I am particularly fond of Audio Note speakers, but, they are a bit more expensive.  They are made to be put near the corner of the room, which is often a plus with small stand-mounted speakers, but, that does mean a shallower soundstage.  Still, at a local dealership, most of the walk-in interest is in Harbeth speakers, but, those that are willing to listen to alternatives, often end up walking out with Audio Note speakers.  There is less of movement in the other direction.