This is a mix of comics, most of them take place before Serenity: Those Left Behind, except the last one that happens after the events of the movie and I thought it was kind of cheesy, even if I liked the character the comic is about very much. 
 In the end, my opinion is completely partial, because I like the TV series and the movie so much that I love to be able to read more adventures of these people, although the comics are too short and doesn't feature enough River IMO... but nevertheless they are good. 
 The drawing style is sometimes very different from one artist to the other and I don't quite like it very much, but well... It's Firefly and I'm happy with it as it is. No complains as long as they keep doing them!!