The biggest misconception of graduate school I see is that you are going to learn science directly from your professors. Even if you learn more from your PI than from any one other person, you will learn far more in aggregate from other trainees than any one professor. https://twitter.com/thoughtsofaphd/status/1300030088428355584

Part of this misconception is that we talk about the PhD as a continuation of just education and not as training. It's not just learning science, but learning how to do science. The latter is harder, but doesn't feel like "learning" the way undergrad coursework does.

Training requires consistent dedicated practice. In my experience as a student, professor, and longtime martial arts instructor, the best environment for this is often with the teacher not present, but with fellow trainees by your side to learn from and exchange feedback with.

Meaning, if a PI sets things up right, it should feel to a student like you're being mentored primarily by everyone else in the lab. It's simply more effective that way. This has important implications in what you should look for during a rotation:

You're looking for three things in a rotation: fit with the lab, fit with the PI, and fit with the science. In that order. All three matter, but if you have to choose, that's the order to choose in.

You've already learned a lot of science as an undergrad, focus on where you'll best learn how to do science and how to be a scientist. Go to a lab where the other trainees in the lab are become the kind of scientist you want to be. That's where you'll learn the most.