Have a big balance of SPG points, thinking to buy 2 travel packages, unsure whether to choose United or Alaska for the miles? Although you get a few more United miles, which can easily be acquired from UR, Alaska miles are hard to come by, which would you do, Alaska or United with the 7 day package.? With the remaining SPG points, when they transfer to Marriott points, will the transfer to airlines remain the same as currently, or will it be devalued? Thanks