I just saw the play over the last two days and I think that the execution of the play was phenomenal. Great effects, great music, great lighting, great characters, great humour...
...but I didn't really like story.
But despite my issues with the story, the play itself was very enjoyable to watch. I didn't like Albus as a character that much, but Scorpius was absolutely brilliant. I'm glad I went and enjoyed the play, but I think anyone who just reads the script will do themselves a disservice. They'll get the shaky story line without any of the impressive performance and execution.