Went, saw it, loved it.  
I have to say, this was BY FAR the largest cross section of society I have ever seen in a theater for a sci fi movie.  Everyone from grandpa to 10 year old kids was packed in there for the early movie this morning, and everyone loved it.  I always thought of Star Trek as having the biggest cross section as fans, and while they may still have the gross numbers, I think this has a better representation of every age group as fans.  Like sci fi movies?  You'll like Serenity.  Like Westerns?  You'll like Serenity, and LOVE Firefly.