I think that--just like any field--the T with life experience and practice dealing with his or her own personal struggles will be more empathic and possibly better able to help you rather than someone who hasn't struggled at all. T's must have supervision and it is in their supervision (if they're not still in regular therapy) that they can continue to unload any stuff that naturally will be triggered in the intense treatment of others. I would hope that they can deal with any unresolved emotional issues that arise and compartmentalize enough so they don't interfere. But inevitably their crap will enter the relationship because, as Peg said, T's are human too! However, if a T's emotional issues crop up again and again then he or she would have to seek special help or take a break for self-care.