Before the show, Marlon Jackson said he respected his siblings' decision, but said he was sure Michael would have approved.
"Each one of us grieves differently," he said. "We want to celebrate the positive side of his life, the positive things that he did."
Some fan groups around also criticized the show for ticket prices that started at about $100 and for what some regard as an out-of-the-way location in Cardiff, 150 miles (240 kilometers) west of London.
"I believe it should wait, not only because of the Murray trial," said Wesley Noorhoff, president of a Dutch Michael Jackson fan club. "If you do a tribute to Michael, it has to be the best there is, just like Michael."
But those who came to Cardiff said it was a fitting antidote to the grim courtroom spectacle in Los Angeles.
"There's a lot of negativity in that courtroom," said Ronnie Lee, a 32-year-old truck driver from Pembroke, Wales, sporting a "Thriller" T-shirt. "This is a chance to say, 'Thank you Michael' and celebrate the music."
Jill Lawless can be reached at: http://twitter.com/JillLawless
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