Both are main lines so neither is a "bad" move.
Nd7 typically can lead (if white wants) to more dynamic play where black has more chances to lose but also has slightly better winning chances.
Bf5 typically leads to more static games that tend to end in a draw more often as black forces white to echange a prime offensive piece.
I have simply question about this position. What is better to play? Nbd7 or Bf5? I have never played Bf5, what's the difference between positions after both moves?