Finally finished watching the DVDs. Disc four was a little too melodramatic (the Sachiko/Yumi tiff wouldn't have happened if they'd just talked like souers should), but the end makes up for it.
Couple of errors. Double-entry for Yumi/Kana Ueda in episode thirteen's English credits. More annoying was the inverted subtitle colors for Special 6; black with yellow outline and black (not transparent) background, which made me think they were setting up a gag about the lighting. Fortunately turning off the subs made it watchable, though I had to remember the translation beforehand or grok the scene on my own.
EDIT: The inverted subtitle colors were just a playback glitch on my DVD player. Worked fine on my laptop, then on the DVD player after reinserting the disc.