all C specials take off a primer, and 22C is safe on block so it's great for guard breaking or ending block strings.
her ABC specials that have special follow-ups can be canceled into their drive versions, even on whiff or block.
even if her opponent is backed up to a corner, 236D will go through them.
22X specials all wall bounce on counter hit. 22A is the fastest and can stuff a LOT of moves, especially at the start of a match.
That's all the important properties I can think of.