As far as the theoretical side - that is, the questions of religious beliefs - he sees three types of attitudes the non-religious might take:
1. Religious belief has no serious intellectual content at all. It is and always has been little more than superstition, the arguments offered in its defense have always been feeble rationalizations, and its claims are easily refuted.
2. Religious belief does have serious intellectual content, has been developed in interesting and sophisticated ways by philosophers and theologians, and was defensible given the scientific and philosophical knowledge available to previous generations. But advances in science and philosophy have now more or less decisively refuted it. Though we can respect the intelligence of an Aquinas or a Maimonides, we can no longer take their views seriously as live options.
3. Religious belief is still intellectually defensible today, but not as defensible as atheism. An intelligent and well-informed person could be persuaded by the arguments presented by the most sophisticated contemporary proponents of a religion, but the arguments of atheists are at the end of the day more plausible.
And as far as religious practice is concerned: rituals, morality, and (I would add) community, he likewise sees three possibilities:
A. Religious practice is mostly or entirely contemptible and something we would all be well rid of. The ritual side of religion is just crude and pointless superstition. Religious morality, where it differs from secular morality, is sheer bigotry. Even where certain moral principles associated with a particular religion have value, their association with the religion is merely an accident of history. Moreover, such principles tend to be distorted by the religious context. They certainly do not in any way depend on religion for their justification.
B. Religious practice has a certain admirable gravitas and it is possible that its ritual and moral aspects fulfill a real human need for some people. We can treat it respectfully, the way an anthropologist might treat the practices of a culture he is studying. But it does not fulfill any universal human need, and the most intelligent, well educated, and morally sophisticated human beings certainly have no need for it.
C. Religious practice fulfills a truly universal or nearly universal human need, but unfortunately it has no rational foundation and its metaphysical presuppositions are probably false. This is a tragedy, for the loss of religious belief will make human life shallower and in other ways leave a gaping void in our lives which cannot plausibly be filled by anything else. It may even have grave social consequences. But it is something we must find a way to live with, for atheism is intellectually unavoidable.
Feser plausibly sees P.Z. Myers and Jerry Coyne as A1 type atheists. But, he says, to hold this position, one must
...think it plausible that the greatest minds of entire civilizations -- Augustine, Aquinas, Maimonides, Avicenna, Averroes, Lao Tzu, Confucius, Mencius, Buddha, Adi Shankara, Ramanuja, et al. -- had for millennia been defending theoretical and practical positions that were not merely mistaken but were in fact nothing more than sheer bigotry and superstition...
On the theoretical side, I would put myself solidly in category 2. I can't imagine how intelligent, educated people today still cling to religion. Actually, I can imagine it, because I used to be one of them. But I find it hard to believe that after looking at all the arguments and evaluating them honestly, someone would conclude that, yes, an invisible person in the sky is more plausible than not.
On the practical question, I place myself somewhere between B and C. I think religion does address fundamental human needs, but I think it does it very imperfectly, and I don't see why we need to introduce supernatural entities to address those needs. (Some of the "greatest minds" Feser mentions didn't see a need for supernatural entities, either: Lao Tze and Buddha, for instance.)
Also, I don't think it's a tragedy that religion is false - I think we can get along fine without it. Maybe even better - but we will have to work on replacing religious institutions with non-religious institutions that address those same needs. We don't have those structures yet.
(Cross posted on Think Atheist.)