Look, it's not badly written, and often funny, and sometimes even a little poignant (although, I don't know how much that was enhanced by Meryl's acting - and she really did act this audiobook, which was a problem in itself). And it's a roman à clef, so it hardly seems fair to accuse it of being too blatantly autobiographical, or too "journal-ish", as many of the more negative reviews here on gr say. But I'll home in on two things that really bothered me.
First, the humour is tremendously mean-spirited. I mean, Rachel is angry, yes, of course, but it's a really dishonest kind of anger veiled as humour: it's sarcastic and passive aggressive, which I suppose is understandable, but it's also just downright mean, and not just on Rachel's part. These people, all of 'em, are really MEAN. Case in point: the group therapy scene/robbery, and there are many other instances like it.
This is a case of Ephron going for the good story, or the cheap joke, at the expense of humanity and compassion or any deeper reflection or insight about character - her own or any other. The irony here is that between the lines, because it's so autobiographical, and because she cites her therapist pointing out this very thing to her as a bit of a gargantuan flaw/blind spot, the reader knows this is not even an authorial choice. This is not Ephron building character, but revealing her own and others'; the real people behind the pseudonyms. No wonder Carl Bernstein wanted the movie stopped.
In a novel where psychoanalysis comes up again and again, it's kind of telling - or something - that this is the general tone throughout.
A related point is the racism, sexism and homophobia of the humour. So, okay, it was the late 70s/early 80s, but still ... ugh. And it's particularly difficult to read this kind of humour (there is, literally, a good ten minutes of a vignette in which the word 'dyke' is repeated about two dozen times) when one is conscious that it is being presented from a particular cynical, sophisticated, albeit self-acknowledged-as-bourgeois POV. These are the New Yorker-reading, consciousness-raising-session-attending, arugula-and-brie eating, psychoanalyzed political-intellectual elite of NYC/Washington of the 70s. I.e., Ephron thinks she can get away with it because she's hip; she's being self-deprecatingly ironic. Another ugh.
And then, finally, there is the fact that I just can't stomach the presentation of marriage - or these kinds of marriages, maybe (?) - as the be-all/end-all state. I don't get these women, and their view of the role of women. I don't get the fat-phobia, the lookism, the heterosexism, the being constantly on the hunt for a man 'coz god forbid you're ever single for more than 10 minutes between your second and third marriage. I don't get, I never did get, believing one is over the hill at 30 or believing a woman without a man is an incomplete and pitiable creature.
I simply can't get any foothold to this particular mindset and the way of living it spawns. I wasn't raised by a mother who expected me to meet those particular standards, or who put that kind of pressure on me - thank god. BUT: I had lots of friends whose mothers did, and lots who were attending university simply for that "MRS" degree; to find and marry a doctor or a lawyer, not to become one themselves.
So I do remember it, the early 80s, and that mind- and soul-numbing culture gap when feminism was lying dormant and on life support between the idealism and political activism of the 60s/70s and the emergence of the third wave of the 90s. Revisiting it in Heartburn was a trip back in time; unpleasant, but blessedly short.
I did like the recipes.
Read at your own risk. And if you consume the audiobook, as I did, know that Meryl Streep -- the premier actor of our generation -- is far too good for audiobooks. Here, omg, she comes off as an over-eager 2nd year acting student auditioning for summer stock.