I used mine for environmental portraiture. The lack of ability to fill the frame with the subject's head made it less than ideal for head-shots. But if you were standing 10 feet away and wanted to show the subject in his/her environment, then it was great. Ditto outdoor weddings, but I never shot one professionally -- only for friends, so I don't have a sense of how one would fit into a pro work-flow. I think you'd want more than one and have a trusty assistant loading the one you weren't shooting. Ultimately I sold mine and bought a guitar. The guitar is good for weddings or street, but not portraiture. I would go with the ubiquitous square format for a wedding (Hassleblad in my case, but Bronica, Rollei etc. for those so inclined).
Ben