If you enjoy handloading the 257 Roberts is a fine caliber. If you don't go with the 25-06. I own both and reach for the 257 more than any other in my arsenal. I can reach an honest 2926 fps with Hornady 117 gr. BTSP out of my Remington 700 with a 22" barrel. With the same bullet I reach 3088 fps with the 25-06. It also has a 22" barrel.

Like stated above if you handload give the Roberts a try. If not stick to the 25-06. One thing to note. My Roberts was a special run of the Remington 700 Stainless Classic. It has a long action. The OAL I use to reach good accuracy is too long for a short actions box magazine. So, I guess if you need a long action for the Roberts why not just buy a 25-06?