Here’s a good interview of Sarah Coakley on how religions compare (or ought to compare) to one another.
Here’s a quote from the video that I think summarizes her main point:
If you simply look at those clashes as extrinsic doctrinal incompatibilities, then you’re not really getting to the heart of the issue. You have to probe more deeply than that. You have to look at the practices, attitudes, and lives that are attending these kinds of propositional assents.
Much more important than a kind of pluralism is how grown up we are as religious people. How deeply we have imbibed our own traditions.
That doesn’t just mean by being fanatical. It meany by how much we have actually absorbed and been transformed by the tradition that we’ve inherited.
Now once we’ve begun to look at the relationship between religious traditions in those two different ways—not as slabs of differentiated religion, nor as simply a matter of competing propositional forms of assent—then you’ve got a terrain that is much more interesting and, you might say, more complicated.Sarah Coakley
To summarize, religions aren’t just sets of propositions. To compare one religion to another based on the veracity of the underlying propositions (about the nature and definition of God, God’s action in the world, etc.) says something, but not everything, about the religions being considered.