I've done a couple of weddings over the years(when on film as well so extra pressure to get the shots 'right' but neither were 'pressure' ones with any expectation of the output) and enjoyed the whole experience. I do believe its important to get one of the 'family' allocated to do the ushering of people so you don't end up being in the bad books with everyone, they seem to accept it from a family member but not from some stroppy photographer
Tony, I'll PM you about coming with you sometime....