I don't know if your fury has made you disingenuous or if that was pre-existing, but I'm basing my info from the reported efficacy rates, 63% versus 92% [1, 2]. I don't know where you got the 70% and 90% figures from or exactly what you mean.
I didn't mention any other factors one would weigh in such a decision, but a rational person would indeed take those into account, as you mention.
But outside of those factors, and any others you could think up, it would be irrational not to prefer the more effective product.
Most people (like me) are not going to get any vaccine for months, and have not had any vaccine for a year since the start of the pandemic. We've been taking precautions, as have other people, such as wearing masks and social distancing. But as the vaccines roll out and become widespread and time passes, those measures will fall away or be reduced and mostly you'll be left with the vaccine for protection.
Given that it's not hard to argue for preferring the mRNA shots.
[1] https://www.who.int/news-room/feature-stories/detail/the-oxf...
[2] https://www.who.int/news-room/feature-stories/detail/the-mod...