Orange Track vs Black Track
I managed to snag some of the old black track off WhatNot and wanted to see if it was worth adding to my drag track. After swapping out 6' of new Orange Track for the 6' of the older black track and running couple dozen runs with the same car, it's safe to say the old high wall black track is not great if your looking for fast drag times. The high walls gives more surface area for rubbing and resistance slowing down your track runs. While it is very cool and feels nostalgic in terms of speed the low wall orange track is better than the old stuff. 
Discussion
Either track is fine. I was thinking about building the interstate system out of Hot Wheels track, and my guess was to use black and gray track. Catch my drift?
Anything that old will have higher walls and should be a little heftier plastic...they got thinner and used less plastic for anything considered "recent." As much as I dig the older high wall tracks, I've found the current day stuff a little more reliable. Plus...the old stuff is harder to find so if you rely too much on it you'll paint yourself into a corner for the future.
The black, yellow, and blue track all have higher sidewalls and are also just a tiny bit thinner than standard orange track. Cars that will easily fit on orange ttack will rub and get jammed on the other kinds of tracks.