Question about forming a 3 peice band or a 4 peice band.?

3 pieces are more charming, especially live. However, when it comes to recording, you may feel like there is a lot of unused empty space being used. If you're going to be a in a 3 man bluesy sounding Black Keys kind of band, I suggest getting a boss loop pedal so you can act as two guitar players and still be a 3 piece.