The 257 has two advantages, flatter trajectory, and less recoil. The flatter trajectory can be an advantage if you have to shoot in the first few hundred yards at unknown ranges. Less recoil is always nice.
The 7's have a lot of advantages. Superb all around caliber, moderate recoil, great long range ballistics, MUCH LESS WIND DRIFT, 500 yards more maximum effective range, double the barrel life of the 257weatherby.....
The win mag is gonna offer more energy on target, better barrel life, and a bit more maximum effective range.
Of the three, I'd choose the 7 by a big margin. I've had great luck with the Senderos. I'd brake it. I just finished installing a brake on one.