Tuesday soon, or sometime this summer? If it's this summer, I wouldn't bother, for sure. I'm pretty sure it's $75 per person for the expedited service. I personally wouldn't pay it, on principle, I guess.
As far as MPC, it costs nothing. I have seen several people state though that the lines for MPC were much shorter than Global Entry. Seems a no-brainer to me. Costs nothing and it could help.