I've owned some pro speakers with constant directivity HF horns. The pair I still use for my band use are EV Sx-100 stage monitors/small venue speakers. These have a CD horn crossed at 1.8 kHz. These sound very good. I used them as my home speakers for several months. The highs sounded better that most of my previous speakers designed for home stereo use. Very clear and natural, no harshness unless it was on the recording.Not sure if this tells you anything about CD drivers in general, but at least it shows that they can work well.
Dave