I have seen Beautiful twice now, and having seen a number of pre-Broadway previews, both successful ("Wicked"), semi-successful ("Legally Blonde," "La Boheme") and unsuccessful ("Lennon," "Lestat"), I feel that this is going to, at the least, be semi-successful. While it sort of functions like a play with songs, the songs are ones many people are going to respond to and enjoy. The weaknesses are nothing that can't be overcome, and hopefully they will make those adjustments.
As sort of a biopic with music, the comparisons to "Jersey Boys" are inevitable, as others have said, but there is a problem in the first act (which needs trimming) in that Carole King was writing songs for other people. So that meant that we would have Carole demoing the song at the studio, then whatever group would swan out and sing it. Which is fine, but there needs to be more "magic." As in, after we just heard Carole sing the song, we don't need to hear another group sing it again, especially when the show never bothers to tell us anything about these other groups. Not to mention that then there's a competition with Barry Mann and Cynthia Weil, so we get to hear all their songs, too. And they are good songs, but it just gets a bit much (the first act is an hour and twenty minutes long, and it feels it).
There is one number with The Shirelles that gets re-worked, but we don't really see that part. If they are going to go that direction, they need to show us more of the development of the music; as fun as many of the songs are, it just seems like a way to give the ensemble something to do. And it's not that they aren't talented (although they must get tired of all the costume changes, even the impressive quick changes), it just starts to drag.
The cast, from ensemble to leads, is great. Jessie Mueller (Carole King) doesn't try to do an imitation, but settles comfortably into selling the emotion, meaning and physicality of the role. She also is one of those rare actresses who can look 16 and 40-ish without either looking weird or awkward. As her husband and lyricist, Gerry Goffin, Jake Epstein is doing something really twitchy and manic, but not quite as twitchy as the first preview I saw, which is good. His voice is clear and nice. Most of the best lines go to Jarrod Spector (Barry Man) and Anika Larsen (Cynthia Weil), who have a charmingly dysfunctional relationship, but I feel like they almost ended up more interesting than Carole/Gerry, which isn't great. Spector gets to use both his rock voice ("Gotta Get Outta This Place") and his "Frankie Valli voice" ("Walking in the Rain"). Jeb Brown is perfect as the slightly crusty but wily producer Don Kirshner, and Liz Larsen has great timing as Carole's mother, Genie Klein.
I'll try not to spoil the whole thing, but I feel like the main weakness is that the show hasn't quite narrowed in on what it all means and how to tell it effectively. I mean, a strip poker game/vacation from hell isn't exactly a "Defying Gravity," or even a "Tommy DeVito owes 250K to the mob," and there's a "dramatic scene" that I'm not sure we even need to see-- the important thing is its effect on Carole, not that it happened. Having looked up some about Gerry Goffin and Carole King since, there are clearly plenty of things that happened in their lives that are way more interesting, but I suppose the writers may be constrained (i.e., don't want to get sued). They did make changes to a confrontation between Carole and Gerry that took it from pathetic and sad-sack to people applauding and Carole seeming a lot stronger, but I don't get why they are spending so much time building up that Gerry has a roving eye-- the audience gets it (and the audience this weekend was very, very engaged). Spend that time on Carole and how she overcame what happened in her life. I get that maybe the parts of her life they feel they can tell aren't incredibly fascinating that they demand a musical, but they went there, so now they need to sell it. And I really hope they can -- this show has a lot of promise, a very talented cast, and is very polished for this stage in the process. I look forward to seeing how it does.
'"Contrairiwise," continued Tweedledee, "if it was so, it might be; and if it were so, it would be; but as it isn't, it ain't. That's logic."'
~Lewis Carroll