I have used the 300 WSM in the ultimate shadow and the Featherweigth and they both were super guns,each shot 1 inch groups or better with the Winchester Power-points or the Fail safes.
The only thingI did not like about the shadow was the no hinge plate,I hate blind magazines.
As for choice I would not buy a 7 WSM just causeI don't think they have caught on.I would chose the 300 or the 270 WSM
BBJ