I currently work as a research assistant for Prof. A on a government funded project which ends this year. I have advised Prof. A that I am interested in pursuing a PhD and that I would like to stay at the institute I am currently at and to potentially complete it with them as well.
My job has ended up being that I do the bulk of my experimental work in Prof. B's group, as they have the necessary tools and expertise to answer the questions we have and I have established a healthy collaboration. As Prof. B's group is more focussed on work closely pertaining to mine, I find myself more engaged in meetings and conversations of the subject matter with this group than of my own with Prof. A.
Prof B. has since offered me to be a PhD student in their group next year, quite insistently, with 60% primary supervision to Prof. B and 40% supervision to Prof. A. Understandably, Prof. A would prefer it be the other way around.
I enjoy working for Prof. A a lot, but can also see working for Prof. B being highly rewarding albeit a little bit tougher on the expectation and 'cracking the whip' front. Both would offer me an excellent PhD opportunity, but with two very distinct outcomes and professional training. I'm a little stuck on how to decide between them.
Is it a better option for me to have Prof. B as my primary supervisor given that's where my professional goals lie, or is it more important to work for someone that I am much more comfortable with and have extensive prior experience with such as Prof. A?