3.5 stars, bumped up to 4 out of love for the series.
Whenever I get the chance to return to Firefly, I'll take it. And there is a lot here that recalls why the show was so good--in the characters, the setting, the dialogue. And beyond nostalgia for the show, there is some fun, adventure storytelling here as well--in both the main story and the bonus episode included at the end.
On the downside, however, without the Whedons handling the writing, the dialogue sometimes feels like someone mimicking the voices of these characters, rather than the characters themselves speaking. The art isn't always the best. And some of the characterization throughout feels as though it revisits conflicts that had seemingly been resolved previously.
So, I didn't love this as much as I hoped I would, but it's great to see these characters in action again, and there is a lot to enjoy here--particularly for those who are already fans of the series.