In its 38th year, the “Magic of Christmas,” the annual holiday celebration presented by the Portland Symphony Orchestra, once again has gotten things right. There is a bit less obvious dazzle than last year, when guest acrobats from the Cirque de la Symphonie performed high above the Merrill Auditorium stage as part of the program, but the soaring instrumental and vocal music, colorful lights and positive spirit were more than enough to make this year’s show another holiday treat. Two takes on a sleigh ride theme established both the sophisticated and folksy charm of the program.