In Photoshop, which tool would you prefer to use to crop a human body from a picture ?

for low level of contrast selection: Polygonal Lasso tool, it enables you to control tracing points.

for high contrast of selection: magnetic lasso tool it works good.

for both of them you have to set Anti-aliasing (smooth out edges) and feathering number (depends on photo resolution)

it depends, every situation is unique, you can't prefer one tool.