I used Margene's for my bridal alterations. I needed a fairly quick turnaround and they were more than able to accommodate. I had them take the dress in about a 1/2 size, shorten straps and add cups to the bra.
I have no clue what's fair for bridal alterations since the WIC has screwed royally with my sense of "cheap" and "expensive". My feeling is that they are in line with other tailors.
Beware that any extra changes you make after your initial fitting will be charged. Kinda obvi... more > --
Chelsea J. Raleigh, NC USA