Thing I hate about the Ike Gauntlet is they keep it at 60 mph...well, they can all keep 60 mph. Not sure how much value that test has then (considering traffic can get in the way and skewer the time), though I (thought I) liked it when they started. But then it's - "don't go over 60!" What's the point then? Close the road, overload the trucks by 1000 lbs or so...and THEN see which one feels better doing it and can do it faster.
The downhill might actually be more useful, how often it needs to be slowed down with the brakes, how hot are the wheels/brakes at the bottom. Conditions less open to being controlled by throttle. Up...up is just dumb unless it's an actual race.