The Velocity is a lot thicker, and it's a much "deader" string. 1) The MF will have more power, probably more feel, 2) Spin may end up being a toss-up as the V is thicker (less spin), but deader, which allows you to swing harder. 3) The MF will give you a higher launch angle (all other things being equal), 4) the V will last longer, 5) the V will give you more control (all other things being equal). In reality, you'd probably want to string the V a few pounds lower than the MF, which would get them closer to performing the same.