I think whether you like The Red Tent or not probably has less to do with whether you are Jewish or Christian than whether you are "progressive" or "orthodox". In my experience, on average, I have found that Reformed Jews tend to like The Red Tent and Orthodox Jews dislike it; liberal Christians tend to like the Red Tent and evangelical Christians tend to dislike it.
What I most didn't like about the book (I'm Christian) was that the male characters were horribly flat. In the Bible, the characters of Jacob and Joseph are more well-rounded; they are humans with both faults and virtues, moments of greatness and of pettiness. In Diamant’s novel, we largely see only one side to these men--the downside. We never get any sense that they are worth caring about, that there is any emotion within in them that we, as readers, can relate to.
As far as theological objections are concerned, I had a few. The author unnecessarily, I believe, alters some segments of the Biblical narrative. She even suggests that the significant, divine naming of Israel was nothing more than Jacob's cowardly choice to change his name so as not to be associated with the slaughter in Schechem. When Rachel steals her father's household idol in the novel, Jacob seems both to know and yet not to care (at least for a long time). In the Bible, however, he thinks no one among him has taken it, and he basically says, "If anyone took it, let him die," in effect unknowingly cursing his beloved wife, who does die later in childbirth. Had Diamant not altered this point, it might have made for some wonderful pathos in the novel.
I felt like the Red Tent was in some ways at least an expression of a growingly popular modern neo-paganism, which incorporates the myth of the universal, goddess/Mother, feminist ideology, and a sort of body/self worship. I don't complain that Anita Diamant made some of the characters pagan; it is clear from the Bible that many early pre Israelites were, and of course, even the Israelites themselves routinely slid back to idol worship. But in The Red Tent, polytheism almost seems to be portrayed as a healthy, feminine alternative to the somewhat deranged patriarchal monotheism of Jacob's fathers. That was my impression when I read it anyway, and I have known Jews who "got that vibe" so to speak, as well as those who don't see it that way.
Christians do tend to get more upset by the altering of Bible stories than Jews, because we do not have a tradition of midrash, but midrash has its rules and structures too--it's not just a make up any story you like tradition. It's a fleshing out, an explanation, not a contradiction.
