I have found that rough video snippets can be just as interesting to fans as full length, polished ones. I posted this to the Cowboy Mouth Facebook page last night. It is just 26 seconds and was taken with an iPhone, but it is already getting a great reaction.
Some things to keep in mind... (1) the video can't be too rough. If the camera is shaking or the audio is completely unintelligible, people won't watch. (2) You need to choose a good snippet. However, what constitutes "good" will be different for everyone. It depends on the band / business, what fans love about them, etc.
This clip works because it captures one of the Cowboy Mouth concert traditions. Audience members bring red, plastic spoons to the shows. (I've heard local Dairy Queens get a surge in traffic before a concert.) And when the band gets to that one point in the song "Everybody Loves Jill"...