Trying to Decide between 2 Advisors for PhD

[Anathem]

Hello fellow grad students,

(First time I spent 1+ hours writing this and then got logged off upon submission...so let's try this again.)

I am a first-year PhD student, and I am trying to decide between two groups, and let's call the advisors A and B. Both advisors are brand new to the university (assistant professors).  B currently has one grad student and is looking for another; A has none and is looking for two.

I am taking a class that A is teaching.  Her works is obviously interesting to me, but there are only certain parts of her projects that relate to what I want to do after graduation (only certain projects are related to energy. The good news is that I would probably be the one working on them).  I like that her work is focused on more of an industry setting (she did her postdoc in industry), and she is also very friendly/personable.  She also has funding for one of her projects from the DOE.

I have not gotten a chance to interact with B as much because she is not teaching this semester.  I would say that her work is more relevant/specialized in what I want to do after graduation, and I also feel like her letter might be worth a lot of weight because she has a lot of papers published, and she also did her postdoc at MIT (although it is probably still too early to tell).  As far as I know, however, she currently has no official funding (although I have no doubt that she will obtain it).  In addition, B is much more straight-forward and let me know what she would expect if I join her group the first day I met her.  I don't want to imply that she is unfriendly, however, but I just thought it would be worth contrasting A and B since I will be spending 5+ years at this university (hopefully not longer lol), and I know warm relations are a necessity.  (I also realize that having a boss that pushes you is important.. so basically I'm unsure of what to consider at this point. Not that A wouldn't push me -- I just think there are different approaches, and since I'm new to the whole grad school setting, I'm not sure which one is more effective.)

I'm leaning toward A because I feel like her lab would have a better work environment, there is funding, and the lab will have more of an industry-feel.  However, for the specific job I want after I graduate, I feel that B's work is more relevant.  I'm hoping some of you could weight in on this.

Thanks for your help!

[St Andrews Lynx]

I'd say that lab dynamics are the PI's personality/management style are more important factors than research interest alignment. At the simplest level, your research interests may change over the next 5 years. Your PI's style is a lot less fluid. 

Since both A & B are very new, I'm not sure how much you can discover about them prior to joining their labs. A person who is nice when teaching still might be demonic towards their grad students. Their funding is all hypothetical until they get grants, and the direction of their fledgling lab research is subject to change (in my own lab they apparently started out investigating X. Topic X never managed to generate anything successful. Then there was a weird side-product that turned into a whole new line of investigative research. The PI needed grants and publications, so they quickly re-angled their lab to take advantage of the projects that gave them these things). 

Regardless, interact with both PIs are much as you can until you need to make a decision. Listen and observe. Go with what your instincts are telling you.