JNJ is an adenovirus vector, so if you wanted a more traditional vaccine technology, that would be a reasonable view to choose them over PFE or MNRA. 1 shot is simpler too, although for all of these immunity builds up over time and the best results they quote are after 1-2 months post vaccine not unlike the 2 shot ones with a 5-6 week time frame for full vaccination.
However, in terms of their efficacy stats, I think this JNJ one looks 2nd tier to me behind PFE, MRNA, or NVAX, where we saw 95% efficacy numbers against the 72% seen for JNJ in the US (avoiding the variant issues that result in their lower foreign trial arm stats). JNJ confounds direct comparison by quoting their efficacy stats against moderate or severe disease (bad enough you have trouble breathing or worse), leaving out the mild cases (ie symptoms + PCR positive, but no need for hospitalization).
They did include a secondary analysis including mild cases, which showed overall trial efficacy in the high 60%’s, not broken down by region, but this was similar to their overall efficacy quoted for moderate/severe so I conclude they are likely similarly effective against mild as they are for the worse cases and hence a fair bit less good than the other vaccines. See page 29 from the FDA presentation I linked above.
Everything we’ve seen shows good but not quite as good vaccine efficacy against the major variants, and given all these vaccines are spike protein based off the Wuhan Classic version, I expect they will fair similarly. Yes, there have been more cases / lower efficacy, but the vast majority of those cases caused by variants in vaccinated people have been in the mild category.
My area is still offering homeless people priority over those who lie about their health issues, and I’m not yet bothering to lie about either of these so I won’t have to make the choice yet to the extent one was offered. But if I had a choice, I’d take one of the higher performing ones (PFE, MRNA, NVAX) over the lesser ones (AZN, JNJ). I suspect any of them will, after appropriate time to build your immunity, prevent the vast vast majority of all serious cases in both the original and variant strains, so in that sense any of these vaccines are still good ones.