I've been reading bits and pieces about these different vaccines in hopes of making an informed decision if there was a choice when they come out. What I sort of understand:
Moderna and Pfizer are using a new approach to vaccines using mRNA codes and this new approach is rather untested and unproven, but its 2020 and a new approach for making vaccines is probably due. Their post vaccination antibody test are showing 2 to 3 times the antibodies of recovered COVID people and that sounds like some serious protection. The down side would be I'm not fond of the idea of having my genetic material artificially altered because on a similar note I'm definitely apprehensive about having my hormones artificially altered and believe that practice causes cancer.
Oxford is using the old approach of using a weakened similar virus which is a highly tested method and proven. It is showing about the same level of antibodies as a recovered COVID person - not quite the same type of antibodies just one that easily adapts. The down side here is that I don't like the idea of transferring altered monkey viruses into me, sounds a rather barbaric way to do things and perhaps a little on the weak side as far as effectiveness.
The CanSino also uses a weakened virus approach, one that comes from a human rather than a monkey, but is a Chinese military creation and who knows where they got it - NOPE, no Chinese vacs for me!
I'm not crazy about vaccines, period. I've went through 3 different types of measles, mumps, chicken pox, rubella and more as a kid and 20 years ago I'd probably been inclined to forgo a vaccine but these days I have some underlying conditions that I don't feel like I like my chances of taking on this type of aggressive respiratory disease.
That said, I'm kind of leaning toward the Pfizer vac and the fact we invested 2 billion $ into 100 million doses of these already shows where the experts are putting their preferences which adds to that leaning that way.
