As I accumulate MP miles, I've been considering using them to upgrade economy seats on a leg of my EWR-MAN flight with my family. However, I realized that UA is charging me for the upgrade. The flight booked in economy is around $2200 r/t, but jumps to $4100 r/t if I upgrade one way with 60k miles. Is this the best use of miles, or am I better off waiting to get enough miles to redeem for flights? Gotta admit I was disappointed when I realized. Thanks in advance for feedback.