Both acts in France, A Chair Act and Le Mime Roland, are wonderful. We adore the Living Statues in Italy and always catch Miyuki the candymaker in Japan several times each trip. Both Voices of Liberty and American Vibe are outstanding vocal groups in America -- I'm not as in to choral music as my dh, but he thinks the Voices are incredible. He also likes the traditional Chinese music (can't think of the name -- it's two women who play inside the lobby of the theater -- but my kids think they are big-time boring. See Off Kilter at least once b/c you've probably never heard anything like them before. The World Showcase Players in Britain are worth watching, but I probably wouldn't plan my schedule around them. The Chinese acrobats are amazing, but I always worry about how those tiny children are being treated.
I'll admit that I didn't think the British Invasion was very good -- singing was a little off and musical skills were not impressive.