Originally Posted by
DELee
Principally leg room. Seats are pretty much the same in terms of recline (the 1"), seat padding (de minimus) and arm rests (you'll still be fighting for the common rest with 21 B or D).
Of course it is considerably better than the 20 C/D pair that can't recline at all.
David
My default advanced seat selection for narrow-body A/C is 21C/D unless there is an empty row in other E+ rows (except for row 20) near departure time.