Circumcision is shown to prevent or lower contraction/transmission of various diseases. Some of this can be replicated via hygiene or the diseases in question are infrequent anyway.
Circumcision has been shown in various studies to both decrease and enhance sexual satisfaction. It's hard to find unbiased data on the topic and some older studies have been discredited. It's also difficult since most males don't get circumcised late in life and so can't provide data on the subject. Those who do typically were circumcised as a solution to some other problem which may have been affecting them sexually. Sexual satisfaction is such a subjective thing anyway that I doubt any concrete data can exist.
Some health benefits of circumcision occur only in neonatal circumcision so delaying the procedure negates these benefits. Also, circumcision in older males is a more difficult procedure than neonatal circumcision.
Compared to female circumcision where the intent is to destroy the sexual (rather than reproductive) function of the organ, male circumcision ain't no thang.
The American medical societies have remained largely neutral on the subject, issuing statements that it does have some benefits but is not medically necessary and should be the informed decision of the parent.
My own opinion is that it has enough benefits to justify it if the parents want to and not enough benefits to warrant castigating someone for deciding against it. Unfortunately, it's one of those topics where the "against" side is much more emotionally invested in arguing against it than the "six of one, half dozen of the other" side is vested in supporting it.