A tiny electric torch running on 3 AAAs, to chase fugitive lens caps etc. maybe backed up wirth an even smaller one. I'm doing stills. If it gets too freaking dark, I'll use flash. What are your goals and needs? - I recommend thinking backwards and fear it takes an enormous amount of LED lighting, to turn an entire venue into a conveniently shootable place. - Will you need 2? 4? or maybe even 16 times of what they already have there? Are you looking for a portable fill light, to make your available light desperadoism look better? Do you have staff to move & aim it?
I have helped out as the Second Photographer on several weddings last year, so I am still keeping my hand in: for Stills neither I nor the bloke I assisted would ever consider LED lighting at the Reception. Flash only. Many reasons, Light output; Motion stopping; ability to drag the shutter for lighting/mood nuances; LEDs mounted on stands etc around the room are generally more cumbersome than a set of Remote Speedlites on table stands (insurance considerations especially); Client and Venue not liking the continuous "light-show" spoiling the "ambience". If your pulling Stills from the Video (which I don't think is a good idea for a range of other reasons) then that's a different kettle of kippers. WW