We just watched Persuasion a short time ago, and the differences between the two heroines- Emma and Anne- are marked. Certainly Anne is the better, more admirable person, but Emma has her own exasperating charm.
I've seen two other adaptations of Emma: a BBC miniseries which also aired in 1996, starring Kate Beckinsale as Emma, and another miniseries on 2009 starring Romola Garai in the title role. I haven't seen the 1996 one in years, but I remember liking it, especially the portrayal of Mr. Knightley by Mark Strong, who was a bit crankier than Jeremy Northam's portrayal, making for a fun contrast. Rather to my surprise, I really enjoyed the 2009 version when I watched it a couple of years ago. As always, miniseries afford the opportunity to explore the story and characters in more depth than a feature length film which is always appreciated. But, having just struggled through the first few episodes of Elementary, the so-called Sherlock Holmes adaptation on television, and given up on it because I found it unlikable, I wasn't enthusiastic about seeing Jonny Lee Miller in the role of one of my favourite Austen heroes. My fears were unjustified; he is really good in the part, and the miniseries as a whole is delightful.
All of these adaptations are worth your time... but read the book first.