Pickuptrucks.com and Cars.com have published a comparison of 2015 midsize trucks. The GMC Canyon SLT came out on top. Entries from Chevrolet, Nissan and Toyota finished in this order.
http://news.pickuptrucks.com/2015/04/2015-midsize-challenge-results.html
One note: "... on high- and low-speed dirt obstacles, the [Chevrolet] Z71 trim (suspension, tires, shocks and decals) was not up to the level of the Nissan Frontier PRO-4X and more specialized Toyota Tacoma TRD Pro."
http://news.pickuptrucks.com/2015/04/2015-midsize-challenge-results.html
One note: "... on high- and low-speed dirt obstacles, the [Chevrolet] Z71 trim (suspension, tires, shocks and decals) was not up to the level of the Nissan Frontier PRO-4X and more specialized Toyota Tacoma TRD Pro."