But selfishly speaking, wouldn't I personally be a lot better off with the 95% effective Pfizer or Moderna vaccine than the 65% effective Johnson & Johnson shot.

Before I get into the reasons that the percentages you cite aren't what they appear to be, let me cite a more important one: 100%, as in "all three of the vaccines you mention were 100% effective at preventing death or hospitalization due to COVID." After that, frankly, the rest is details.

during the late summer and fall, when COVID cases were at a low ebb—so low that not only did no one in Pfizer's vaccinated group die of COVID, nobody in its placebo group did either?

The Johnson & Johnson shot, meanwhile, was in the field during the winter spike in cases.

Its study also included Brazil and South Africa—each home to a new COVID variant—as well as the U.S., and there were a quite respectable five COVID deaths in the placebo group (and none in the vaccinated group, as above).

In fact, if I was a flack for Johnson & Johnson who drank too much on Twitter, I could plausibly boast that my company's shot was the only one battle-tested against the so-called South Africa variant.