Also check out his slightly more deranged second channel, NileBlue. I love his videos because they really show the whole scientific process, errors and all
What I remember:
They smelled a little like grapes, but they just tasted like a sub-par apple. They were also harder/dense than normal apples, and were expensive.
Cotton candy grapes and Pineberries are natural cultivars as well. Stewing apples in a vat of grape flavor just isn't appealing to me,, no matter how FDA compliant the process is.