the virtual radar type displays are of little use
Not in my experience - the display is scalable to show just immediate threats. I run with minimum distance and heights above/below (as I mentioned) as a belt a braces back up to the aural alerts. A glance at that device takes a second and can be incorporated in a systematic external scan.
Mooneyboy - you can get ear bud type bluetooth headphones that can be worn under your DC headset to receive the voice call outs just as well as $1000 Bose units.