Yeah nice speaker...they do sound like there more in your quest.The atc are musical and natural to my ears, but the harbeth are sweet musical.I think that there are trade offs with everything/speakers.Harbeths played at lower vol is a +.
Harbeth...older iteration...probably newer crossover updates/changes,metal tweeter?
Atc ...Will throw a nice sound stage...need to have some vol to get things up and running.Wont have the throw the harbeth have... just physics/cab volume.