The 358 is a little TOO slow IMHO. You don't NEED 400 yard trajectories, but the 358 is more like the 30-30. MAYBE 200 yards, less if you're shooting big critters.
Comparing 225's to 225's, the 338 is just as fast (both around 2500 fps), with a better BC & SD to extend the range a bit. To compare apples to apples, you have to compare bullets of similar SD's, to really the comparison has to be between the 225 grain in the 338 (at around 2500fps) and the 250 grain in the 358 (at 2300 fps). Then it's really no contest, with the 338 having the velocity and trajectory advantage, and a slight trajectory advantage which grows as the range increases.
I don't know what it is or understand it, but the same is true between the Whelen and the 338-06. Using the same parent case and the same 225gr bullet weght, the 338-06 has a higher MV than its .358 sibling. This is true according to all the load manuals that I have that list both calibers (several of them). Hell, this phenomena is true even of 250 grainers. See
http://www.hodgdon.com/data/rifle/33806.php and
http://www.hodgdon.com/data/rifle/35whel.php
So. IMHO, the 358 is like a 30-30 on steroids. Similar trajectory and range, but packing moose- and elk-smashing power. The 338 federal carries virtually the same power, but to a slightly farther range. The extra 200 fps or so buys you 50 to 100 extra yards when sighted for an 8" MPBR.
But at the end, the differences are mostly acedemic. The chioce would really boil down to which ever you could find chambered in the rifle you want.