I do love Avantis but, for whatever reason, I have not seen one in ages.  The distinctive sound used to be something I would see quite a bit in the Midwest before Avantair went bust and their frequent appearances abruptly stopped.  To see this one show up was a nice treat.  I have yet to see one of the latest EVO versions.  They have a five bladed prop instead of the six bladed version on the previous iterations so I have yet to find out how much the tone has changed.