If your going to be shooting bullets of 100 grains or lighter, the 25 WSM will dang near match the much larger rounds. It will easily match the Wby and be within 100 fps to 150 fps of the STW and banshee especially with bullets under 100 grains.
The performance of the STW and Banshee is pretty much identical. There really is no difference between them other then the RWS case being able to be loaded to higher pressures and that may show some increase in max performance. Still cases are hard to find and expensive.
If you want an ultra performance 25 cal, the STW is hard to beat, easy to form cases, alot of performance and relatively user friendly as far as loading.
Again, if you want a higher volume shooter and would be able to give up a bit of velocity for more barrel life, the 25 WSM would be a great choice.
Kirby Allen(50)