I would give totally different reviews to the two halves of Mamma Mia!. Act One is sweet trivia of no consequence, with a couple of cute songs and some oldies but goodies that work fine. But the enthusiasm on the stage doesn't quite conquer the inane dialogue and foolish plot to reach the audience. The not-very-imaginative choreography is all right on the beat, with most people doing exactly the same thing at the same time. The costumes are a mish-mash of decades. However, in Act Two the pretense of a story is just about dropped, and as they reach the expected conclusion, the show becomes just a concert of ABBA's best songs, done well by the very talented cast (especially Louise Pitre Judy Kaye and David W. Keeley), with great flair in the costumes and the audience on its feet almost dancing to the old disco beat.
