The costuming is absolutely superb. My mother would have loved it. The dresses are so accurate...the Brits know their history. I think with each film production of something Austen (speaking from the English perspective as they produce these films) each becomes innately more accurate to the period of style as it pertains to the history of women's fashion, they have become less hollywoodistic in their approach to costuming and more typical and truer to the historic form of how authentic the costumes should be. Take for instance the version of Pride and Prejudice with Collin Firth, the costuming in that series is a bit off...even though it is fun to watch!! Oh and don't forget the forgettable supposedly introspective Becoming Jane (I don't think the Brits produced that film though)...what a disaster....I almost cringe when I think of how they make Anne Hathaway on the same level as Jane Austen, very badly done.
I especially like this version because the depth of the character in Emma is really manifested in how she portrays herself by the perfectly fitted Romola Garai. In other versions she is seen in only one light, superficial, in this version you see her many layers, the layers Austen speaks of in her Novel. Interestingly, Emma truly was a woman far beyond her time. She was an England Regency Feminist...who would have thought that this beautiful woman would choose not to marry. How absolutely outrageous! That, I think is why Jane Austen's books are still so beloved in this generation. She has still managed to relate to women beyond her own life.
I've only seen it once and am dying to delve into it yet again and again and again....this of course is just my first impression.