I've never owned a Whelen, but I think you have pretty well summed it up. Maybe a wee bit of velocity edge to the Whelen with full loads, but the x57 in a modern rifle is quite surprising in its range of velocities. It is a very "modern" cartridge.

It is just beyond the velocity level of the x57 that recoil takes a big jump, too, making the 9.3x57 a VERY shootable cartridge. And, as Daryl has oftimes stated, the modern x57 performance level just about equals the level of the 9.3x62 of olden days when that grand old killer gained and earned its great reputation.

For years, .35 bullets had a reputation for being soft, and tho there are lots avilable, I am not sure what performance level they maintain throughout the range of weights. They DO include cheap revolver rounds for plinking.

With the availability of resizing from .375 down {with cheap resizing dies available}, the 9.3 caliber really doubles, or more, its bullet availablity.

The Whelen has in theory a sectional density advantage when equal weight bullets are used between the two cartridges, bullets that can be shot to equal velocities due to the Whelen's wee-bit-bigger case volume, but I show my hand in saying "theoretical" since I don't think it would amount to anything in the field that a critter would notice and barely shows up on paper.

The more I hunt with and shoot the 9.3x57, the more I think of it as a highly modern, efficient cartridge. Looking at Norma's factory ballistics or others jogging along at 38,000 cup or whatever and the 9.3x57 looks a bit like a .35 Remington with a cup of strong coffee in its belly, but in reality, loaded in a good action to similar pressure levels, I would take it over the Whelen {and did}, though I would not refuse the gift of a .35 Whelen were one to be given me! It, too is a great cartridge.