I got Moderna for my first two shots back in the spring because that is all that the vaccine clinic had to offer me at the time.
I got Johnson and Johnson for my booster. And I did so by choice. Actually I had to really search for a place that would give me a Johnson & Johnson booster.
What I'm planning to do is alternate between viral vector vaccines like Johnson & Johnson and AstraZeneca, and mRNA/protein vaccines like Pfizer, Moderna, and Novavax. I'm also planning to rotate between different vaccines.
So for my next booster I'll do Novavax if they are finally on the market. Currently they are having trouble producing it in the volumes that are needed in order to go to market. If not I'll do Pfizer.
After that I'll be back to viral vector vaccines and hopefully AstraZeneca will be approved in the US by then.
After that I'll do either Pfizer or Novavax, whichever I didn't do previously.