Is there a difference between poached and steamed chicken?
I would say its a matter of personal preference.  One method or the other doesn't mean your chicken will turn out jucier, either of those methods can dry chicken out if not done properly.  For your application, just cook the chicken how ever you enjoy it the best whether its those methods listed, grilling, frying, etc.  As long as you cook the meat properly it will stay juicy and tender.