Cuco said
Me and Sachiko happen to agree on this one Don't try and tell me she wasn't trying to be reasonable at first.
Mmmm. Personally, I think the whole situation is interesting, and I'm of the opinion that they're both as bad as each other. Sachiko judges Leiko before she's even met her properly, and her apology, whilst made, wasn't sincere.
Leiko on the other hand, IS a stuck up brat. Not to mention she prizes her flyers' condition more than Sachiko's condition, which is pretty damn conceited. Her feathers are further ruffled when Rui helps Sachiko first, so she concentrates on the person who does help her, which happens to be Kami.
Obviously, this sets off Sachiko's already short fuse as Leiko is being rude, hence the swearing and in-your-face confrontation, which whilst understandable, isn't really warranted since Leiko doesn't really do anything to her besides being a bit spiteful.
TL;DR: They're both bitches IMO.