I had both at...60x4.5x35 the Mission at 1000ab, the 715t at 2000ab.....the 715T was just purely more ball, 4-5 boards stronger and started up a foot earlier for me. I actually also have a 505T at 2000ab (drilled the same as 715T and Mission), which is my favorite ball, and also 2-3 stronger than the Mission was......
Just recently I put the 715T at 1000 and kept the 505T at 2000......On a heavier house shot the 715T is 3-4 boards stronger than 505T and a slight bit earlier. One my regular house shot, I see the same but the 715T is not usable past first game at 1000ab.
I like the Track "T" balls a lot! I dont have the Mission anymore! I also have recently purchased a Bank Pearl which compliments the T balls very well.....
The Mission was a good ball for me, but not a great ball for me.
Arsenal:
715T.....................Heavy
505T.....................Med Heavy
Bank Pearl.............MedHeavy/Medium
Dark Star...............Medium/Medium Light
Red Backlash.........Med Light/Light