But many traditional varieties are much nicer than the Red Delicious... I've never eaten one right off a tree, but the R.D.s that make it into stores seem to be pretty bland and "one-dimensional" (purely sweet, no noticeable sourness or other tastes), and often have a sort of nasty bitter tasting skin.

[I notice that Fuji apples are a R.D. cross from the 1930s... But Fuji are vastly tastier (and more attractive!)...]