I think there are a few old threads on this topic, but well, interesting to see if preferences have changed For me it's structured at first, but over time I've grown to love the sag (but NOT extreme sag). I've ditched my speedy shaper but still swear by the purse organiser that gives it some structure without the boxy feel.
I prefer my Speedy with a little sag! Being overly structured/stiff makes it look a bit too utilitarian to me. However, I think TOO much sagging looks sloppy...