willgolf,
I have not made any sort of direct comparison between Charney and Avantgarde (I've heard the Charney more recently), so at best I can recall my impressions of the two. The Charney sounds extraordinarily coherent from top to bottom (not surprising given that it is a single driver speaker). The Avantgardes have a little bit of a problem with the bass matching the midrange and some unevenness in the bass. But, the Avantgarde goes lower in bass and you can adjust the bass to be extremely strong, if that is what you want. Both are very good systems.
There have been mention of several other horn systems or systems that share the characteristics of horn systems that are certainly worth looking into. The Classic Audio Reproduction field-coil speakers and the JBL Hartsfield reproduction, the Horning speakers, and Volti speakers I'e heard and generally like. They are lively sounding system, which I like, but, they are not my personal favorites, but this is entirely a matter of taste, so you must hear them yourself to decide.