I was also lucky enough to attend the Pittsburgh production of the Symphony on July 23. I was, shall we say, less than impressed with Mr. Boyd's performance, however. I was rather expecting him to actually go out on stage and sing his solo. Instead, he simply stood up in his stage-right box, they shone a spotlight on him, and he sang from there. From where I was sitting (stage-right balcony), you could hardly see him. His voice was the same as in the movie, though I wish that the techs had turned up the sound on him; you could hardly hear him over the string section when they came in toward the end of his solo.
Apart from that minor caveat, though, it was a wonderful performance. The tickets were worth every penny. Now, to find myself a CD of the Symphony...