I saw this yesterday and overall enjoyed it. I agree with some of the criticisms above - definitely could use trimming, though it was only 3 hours when I saw it, not 3.5. Essentially Ed Harris and Amy Madigan play therapists in a small town, and the show is made up mostly of various sessions and interactions they have with patients and with each other. For me, what made the show a mixed bag was that some of the patient storylines were much less interesting that others. I liked the stuff with the little girl, the stuff with Ed Harris' mother, and I liked Mark Linn-Baker's character. The stuff with Maulik Pancholy was just ok, and F. Murray Abraham's sections were really dull and tedious for me - and they do take up a lot of time. I should clarify that none of this is a reflection on the actors: the entire cast is excellent and, as the poster above said, they do the best with what they're given. Honestly though, as much as I love him as an actor, if F. Murray Abraham's entire character were cut, I might have liked the show as a whole a lot more.
Overall though, there was enough good stuff that I walked away very moved. I even got teary-eyed a few times. I liked the bits of music throughout, personally, andI liked the lighting a lot. Definitely a messy and inconsistent play, with some tedious parts - but I wouldn't call the whole thing tedious at all. I'd say if you're eager to see the cast, go for it.
I got a $32 rush seat an hour before curtain (that's when they start selling rush). Definitely worth it. I seemed to be the only one there for rush, so it seems pretty easy.