The wow factor is there, 100%...if you are a Harry Potter fan, it's a must see, for sure...the tricks, magic, production value, sets, costumes, all very wizardly and certainly worth the price of admission. The characters are great and the acting is superb, for sure.
Yes, the, "however" part: LONG. Common trend in comments, yes...we did the Wednesday afternoon/evening showing, grabbing dinner at STK Midtown in between (highly recommend, btw) and it was SOO LONG.
The narrative - at times - seemed very over dramatic or soap opera-esk type of dragging on of some plot lines...going in having experienced Universal's Harry Potter World in Orlando, knowing the trickery, action, dragons, spells, etc, I expected more in that regard.
Again - self proclaimed muggle, who happily brought wife for her birthday who LOVED IT but also agreed, some of it was a little dry and made it a bit too long...."I could watch any of the movies for hours on end...this play, not so much."