A wedding pro needs a pro quality bracket that keeps the flash directly over the lens axis, to drop the shadows behind the subjects where they are not seen (unlike objectionable side shadows!). Three products meet that requirement...Newton Camera Brackets, RRS, and Custom Brackets. The CB is a heavy beast compared to the weight of the Newton and RRS...almost 1 lb. heavier than RRS and Newton, and carrying that for 8-12 hours while covering a wedding is not fun! RRS is very expensive. That brings us to Newton...lightweight (my Newton flash rotator is 8 oz.), sturdy, pro grade product. But you need to spend $200 for the Newton or $300 or more for the others!
Virtually every wedding pro who I have told about the Newton and purchased one has loved it and become avid supporters of the product, too! I wish Robert Newton would put me on commission, but I need to refer 999,918 more buying customers first, to get an attaboy!
I have used a Newton for almost 20 years, the bracket on a Bronica ETRSi with Metz 45CL potatomasher flash, and now with a Canon 40D with Metz 54MZ hotshoe flash...it is easily adjusted, and can accomodate tall bodies (1Ds) or bodies with Battery Grips (e.g. 5DII) or without battery grips. Newton even offers extensions to put hotshoe flashes up taller, if redeye is a concern. It could be a problem when you are at 200mm FL and farther from the subject!
I like to use a very small softbox on my on-bracket flash, to soften any visible shadows (like the ones cast by the bride's arm and bouquet while holding the bouquet in front of her below the bodice of her gown).
Newton brackets come either as flash rotators, or as camera rotators. Using a flash rotator on a tripod mounted camera in Portrait orientation, and flipping back to Landscape is easiest with camera rotator, but not horrible with a flash rotator.
PS Products like LightSphere or Stoffen, which rely upon the ceiling to soften light, are useless outdoors...wastes power, gobbles up battery charge in doing so. Remove them outdoors!