This show's going to be BIG when it hits Broadway. I'm talking Hairspray big.
It's one of the funniest shows I've seen in a really long time. The main characters are brilliant, and the writing is very funny.
Brian D'Arcy James was great as Shrek and Sutton Foster as Fiona was uncannily like the movie version. It was scary at times.
I was particularly struck by the scene where they introduced Fiona. They had three actresses playing the part of Fiona - at age 7, 15 and 25ish, they each sang part of the same song. It was beautiful and really touching.
Not surprisingly the show had some rough moments, but in it still was one of the best shows I've seen in a long while.
One very nice touch in the show is that just as the movie of Shrek had lots of clever references to classic fairy tales, the musical version of Shrek is filled with clever references to other Broadway shows. For instance, there's a scene where the fairy tale characters are all interviewed by Lord Farquaad (the villain). The characters all stand in a line on stage and Farquaad interviews them using the "G_d Mike" (as Daniel calls it). The characters then sing a clever song about how they want Farquaad to pick them. It's a pastiche of A Chorus Line. Other shows we saw referenced were Wicked, The Lion King, Avenue Q, High School Musical and others.
Over the past few years, I've seen 6 different shows on tryouts in Seattle: Hairspray, Princesses, The Wedding Singer, Young Frankenstein, Lone Star Love and Shrek. After seeing the shows, I've accurately predicted how 5 of the six would do (Princesses and Lone Star Love disappeared, The Wedding Singer was a pretty good success, Young Frankenstein was funny and was a hit but isn't nearly as good as The Producers was, and of course Hairspray was utterly huge). I honestly think that Shrek could top Hairspray. It is THAT good.
So go see Shrek if you can. If you can't see it in Seattle, get tickets to see it on Broadway. You won't be disappointed.
 Disclaimer: The show I saw is in VERY early tryouts. So far, they've had exactly 4 performances in front of a live audience. It's entirely possible that anything or everything I saw tonight might change before it hits Broadway.
 The Avenue Q reference was when the character of Pinocchio, played by John Tartaglia says that he's going to make a mix tape for someone else (if you've seen Avenue Q, in it Princeton makes a mix tape for Kate Monster). What makes this bit particularly funny is that John Tartaglia originated the role of Princeton in Avenue Q.