"whichever one is available to you" is still the right answer since as some other comments suggest there isn't enough data, yet. For sure one is likely better than the others. If we had the data we'd make the choice, but it seems it's not possible to know yet. The better one may be the one that protects against the variant that is forming via mutation right now in some person in Iowa. But yeah, we don't know yet. So you can wait until we know more, for sure eventually in retrospect we may see there is a clear vaccine winner. But really today just get one, or wait and see which one is the winner, with the risks associated with waiting. I think that's the free-agent adult pants decision.

Also, let's say you get vaccine A today. And in 6 months, it turns out you really wanted vaccine B since it's way more effective it turns out. Why can't you just get vaccine B in 6 months? I imagine if vaccine B is the clear winner, they are going to crank up production on that one as much as they can?