The 257 Roberts is popular on sites like this because it has a "cool factor" and rifle looneys mostly load their own ammo and are able to tailor a load, or loads, that shoots good groups in his/her rifles. It isn't popular among average hunter/shooter because factory rifles and ammo are both fairly uncommon in most places.
I've been shooting the 257 Roberts for over 50 years in both standard and AI formats. I currently have 11 standards and 2 AIs. It is a good cartridge if you reload, not so much if you depend on factory ammo, I have come to the conclusion that the 243 will do almost anything that a person would buy a 257 Roberts for and do it easier and at a lower cost.
Being a 257 and 257AI guy, I didn't get my first 25-06 until later in life, but now like it pretty well. I like the 25 WSSM more than any of the other .257" bore cartridges because I like the Winchester/USRA 70 WSSMs, speed in a handier size rifle.
