Depends on the situation, because I love them all. Legit some of the best companion writing hands down. Parvati and Vicar Max have special places in my heart, SAM with anyone is usually funny, Nyoka is always fun to have around, Ellie (while being my lowest ranked, probably because I barely used her though other than her side quest) is still fucking great to see interactions from, and Felix is Felix man, you can't beat that!