I totally appreciate this. So for one, the inability to influence the project is definitely my most speculative comment - I have heard that rumoured, but I'd have to wait until I did a rotation in the lab and spoken to actual students before I judge whether it really is that way. The rest (namely that he is a slave driver) is assured. But my counterpoint is this, and probably it will be hubris on my part - for my area of research (molecular biology/biochemistry), I think the logic of experimental design and analysis is fairly straightforward, and I feel it isn't a rate-limiting step in one's scientific development. I've run a journal club analysing papers in this area for some two years with fellow undergrads as well as staff I persuade to join in. Again, erroneously no doubt, I think I mostly get the big picture - I'm always thinking of experiments to prove or disprove this or that imaginary molecular mechanism, and I'm at a point where I can see when key controls are missed from published research and when the claims made are occasionally not fully backed up by data. For my specific topic - signal transduction - much research is often formulaic and predictable (not always!).

I've been told by my undergrad thesis and summer research supervisors that in terms of the literature I am ahead and intellectually I have no issues, but both have also commented that my practical lab skills could use some serious work. So while a pretty deep instinct to mental masturbation does drive me to the hands-off PI who lets me do my own thing, in a sense I think what I may need more than anything is real training to increase my efficiency as a worker.

That's just one side of the dialectic though and I'm only putting across a 'Devil's advocate' - I agree with your comment and I would be stupid not to take this decision very seriously and use the rotation wisely.