I haven't heard the Volti's per se, but I have heard a friend's Klipshorns that have been upgraded to the Volti midrange and tweeter horn and drivers and a new 15" woofer in the Klipsh cabinet. So in effect it is a slightly larger Volti with parts manufactured by Volti.
They are far better than the Klipshorns, sounding so un-horn like. They actually image like a very good cone or paneland sound recessed in their soundstage, not in your face like a typical horn. Very nice, even, warm, transparent and extended. Overall I was extremely impressed.
If you can hear them you definitely should. There is something special going on there, for sure.