Nice collection, you opening up a Hoka museum DV? Which are your favourites?
I'm most interested in the various claims regarding a reduced recovery time after longer events. Just like you JeremyG, 50 miles in my trail shoes is ok but I don't think I'd like to do another 50 on top and wonder what state my feet/legs would be in if I did.
I guess 100 miles is always going to ruin you to a certain degree but I'm hoping the Hoka's might mean I'm less ruined. Only one way to find out 
As others have suggested, they may make quite a nice shoe swap halfway if not wanting to run the whole thing in them also.