Jim,
Your #2 seems both true and false.  Yes, more spread because the darn thing is huge but at the same time it focuses the light toward a center point.  If I stand 8 feet away, there is a stop or two of light falloff at my feet versus my face that I wouldn't have with a 36" umbrella.  Now at 12 or 15  feet away you just get a pretty even spread but still a quick falloff where the light is not focused.