Haskell: Prefer pattern-matching or member access?

Suppose I have a Vector datatype defined as follows:

data Vector = Vector { x :: Double
                     , y :: Double
                     , z :: Double
                     }

Would it be more usual to define functions against it using member access:

vecAddA v w
    = Vector (x v + x w)
             (y v + y w)
             (z v + z w)

Or using pattern-matching:

vecAddB (Vector vx vy vz) (Vector wx wy wz)
    = Vector (vx + wx)
             (vy + wy)
             (vz + wz)

(Apologies if I've got any of the terminology incorrect).