I have been reading the frump thread from last month - am both fascinated and appalled in equal measure, as is probably the norm 
But then i got to thinking about a brand who I quite like, sometimes, at least for leather goods, even if many of their clothes are a bit swampy....not as bad as Toast, but, you know.
The brand is A.P.C France.
Here is a link to the robe/dress section:
www.apc.fr/wwuk/women/ready-to-wear/dresses_m117.html
I guess I love them, and have been an A.P.C kind of girl for over a decade now, am in my early 40's and still find much of their stuff quite relevant to me.
But a lot of what was described as frumpy rang a bell, as many of the dresses are sack-like, and a lot of their skirts and blouses are very 'prison uniform' or slightly military, or even benzo'd housewife in the 50's leaning.
I like this, and care not about la frumpage, but since A.P.C seem to get a lot of cool points in fashion blog circles, i am interested in your opinion on their stuff.
What makes one sack-like dress frumpy and the other chic?