To be honest, I've been a bit intimidated by this debate, because to answer it in the context that Feser lays out I would need to have the kind of historical understanding of both Islam and Christianity, as well as a rock solid timeline of Eureopean history, which I don't. But you do :) Which is why I've been more interested in what you have to say.
I think the only thing I have to say in response to Feser is, you look to your religion and I'll look to mine. I think the comparisons and analogies are valid when you and Dan discuss them, but Feser's goal seems to be polemic defense of Christianity and using Islam as foil. I am just not able to take it seriously as a legitimate argument (though the responses his essay spurred form you and others have been very legitimate, and immensely educational).
Considering that my posts aren't worth all that much than you pay for them, thanks for the kind words.
A college-era girlfriend of mine used to read me passages from a book called the Towers of Trebizon, about a couple of women accompanied by an Anglican minister on a tour of Turkey. I remember the book was very funny, but the only passage that has stuck in my mind over the years is one in which the minister complains about how useless the English-Turkish phrasebook is. All one can do with it is order breakfast, or ask for clean towels in the hotel; it doesn't have anything useful like how to say "Christianity is better than Islam" in Turkish.
I think Feser's piece is a bit like that Anglican minister, although it's not so much Christianity, but rather Catholicism, that he's extolling.
Feser column has very little to do with Islam. He is really trying to attack protestantism. The line of argument goes: Islam is bad. Becuase it is not enough like Catholicism. Implying it is like protestantism. Protestantism is bad.
It reminds me of a post Sept. 11 National Review article that talked about the inherently socialist tendencies in Islam.
(TCS is mostly discredited now isn't it?)