....I just want to say they are both difficult jumps, and you can't just argue which one is harder. It just depends on each skater.
I agree that the difficulty of moves, in general, varies according to a particular skater's gifts.
Here are examples. The lutz is considered to be a difficult jump, but Michael Weiss appeared to find it easier than some other jumps. Timothy Goebel mastered quads, but had trouble coping with the triple axel. I remember that, in his prime, Chengjiang Li said that he found the lutz really hard to do, although Chengjiang did other jumps with great aplomb back then, including quads.
Generalizations for scoring purposes have to be made about the difficulty of various moves, but, in the end, what is extremely difficult for one person, may be much easier for another.