I think that one of the problems with this round is that it is the old 250-3000 or 250 Savage in a new package. Sure it a good round, but there is a factory rround out there with Identical balistacs, so why form brass and spend money for custom dies?
Even if both had zero factory component support, I'd rather shoot the .250 Savage than the .25 Souper. My interest in the .250 Savage is allied to my interest in the Ruger M77RL "Ultralight" bolt action rifle. On that platform, I think the .250 Savage is about ideal because its combustion chamber volume v. bore diameter results in a fairly efficient expansion ratio and as a result, the .250 Savage firing 120 grain bullets performs about as good as it can in the "Ultralight's" twenty-inch barrel. The body taper of the .250 Savage has a negative impact on case life, but the plus side is that those stubby little suckers feed and cycle through a short-action turn-bolt gun with "ought-six in a long action" smoothness because of that body taper.
I think the .25 Souper is probably closer ballistically to the .257 Roberts, in the same way that a 7mm-08 is essentially a 7mm Mauser that can feed through a "short" ala ".308 size" bolt action. I might rather have the .25 Souper than the Roberts because of that, but I'd really rather have a .260 Remington or better yet, a 6.5mm Creedmore, than the .25 Souper...