The 308 Win, 338 Federal and 358 Win are all superb SA big game chambers. Other than wanting one or the other for pure preference there isn't a great deal of difference between them in most respects. For some reason the 338 and 358 get some good press with their use of 210 gr Partition and 225 gr Partition loads. What gets lost is the 308 Win and its use of the 200 gr Partition. A close examination of the 308 Win loaded with a 200 gr Partition reveals pretty similar characteristics to the other two loads. Using 200 yd zero and ballistics at 300 yds shows downrange energy/drop/10 mph wind drift:

-308 Win 200 gr Partition-BC .481-SD .301 @2,450 fps MV: 1,775 ft-lbs/-10.2"/7"

-338 Fed 210 gr Partition-BC .400-SD .263 @2,600 fps MV: 1,947 ft-lbs/-9.3"/7.9"

-358 Win 225 gr Partition-BC .430-SD .251 @2,450 fps MV: 1,895 ft-lbs/-10.4"/7.9"

For any game animal hit with one of these loads I doubt you would see any real world difference. Given the 358 opens up a sizable hole and has the heavier bullet you could claim it the better for close quarter work. The 338 Federal w/210 Partition load shows slightly more power at extended range, but nothing significant over the other two. Point is the 308 Win w/200 Partition load holds its own very well against the other two and is a more versatile cartridge with 110 gr - 200 gr loads. Not knocking the other two at all and am a big fan, just showing that the 308 Win is still possibly the most versatile SA chamber. BTW for any who still put stock in a projectiles penetration per SD, the 308 Win is a real driver in that category. Maybe you should just load some 200 gr Partitions in your 308 Win and see how they do.