Hi Mark,
I have a Dax40 and Ian Anderson too. The Dax is slightly higher, but for tall people that makes it a good choice. Mine is 41.5" with a 4" ground clearance front.
You would be hard pushed to see the differences when side by side with other makes, so definitely not an 'odball' but I found the quick way to spot a Dax is the extra inch or so between the rear side intake and the sill. Have a look on the GTD40 web site at my video from Goodwood 2004 see if you can spot the Dax among the grid display.
I would guess that the Dax is slightly heavier since it seems to have a robust chassis, but not by much, and the chassis was designed by John Tojeiro too. In all respects it seems to compare well with other spaceframe chassis replicas, and I guess pricewise it should be similar given similar engine, brakes and equipment spec.
regards
Dave