Check for portabillity
Yup, that's what everyone says. I just read a new wedding videography book that minimized the necessity of even using tripods - they say to use them during the ceremony, but during preps and rehearsal you may not have time to mess with a tripod.
I say BULL&$@* (translation: "poppycock") !
My competitors make it so easy to compete against them because they do way too much handheld stuff. Unless you're going for a special effect that calls for a specific type of camera movement that can't be done on a tripod - unless your subject is in motion or your camera is in motion (for a reason) or both, you need to be on a tripod.
Not just any old tripod either. Unless you're backpacking miles from civilization and just cannot bring the weight, I say "forget portability". What you need is a stable platform from which you can get smooth pans and tilts. That's the most important criteria.
The reason most wedding videographers only use highlights in their demo videos is that there is too much camera shaking, too much reliance on automatic exposure and focus and use of just one single mic. You can't sit through a whole wedding video done like this and not get nauseous!
Nuts to portability. Get a good solid set of sticks with a really decent fluid head. Then hit the gym so that lugging it all around won't have you dragging before the reception is over.
Just off the top of my head, I think the total weight of my sticks, head, camera and mounted gear goes just about twenty-five pounds, yet I'm all over the place with it. My wife lugs about fifteen pounds with her sticks, etc. and she never takes the camera off the tripod. She moves around so fast that we have to use comm gear to stay in touch!