Clint,
Heres the basic rundown...
If you are planning on loading heavy for caliber bullets, with both cases near their max capability velocity wise, in a rifle that will be the same weight for either case, recoil will be nearly identical. I doubt anybody but the most recoil sensative could tell the differance.
I know I can't, especially in a heavier rifle like moat of us shoot at LR.
The strength of the 7mm lies in its exterior ballistics. 168-180gr bullets with their high BC require few moa at LR, and buck the wind quite well. Better than anthing you can throw from the 300WM in fact.
The strength of the 30 lies in its terminal ballistics 190-220gr bullets retain high velocity at LR and land with authority. Noticabely more authority than lesser bullets.
Now then, just how much differance is there? really not a lot. There are folks here who have killed elk at LR with the bigger 7mms, so they obviously do ok, and there have been thousands taken with the 300WM, so they do ok as well. The differance in trajectory is there, but unless you are planning to shoot at 1200+yds, the differance is not pronounced. at 1K the 220SMK from a 300WM will drift 1" per mph more than the 180 Berger from the 7mag. trajectory wise at 1200, there is only 5 moa differance, virtually meaningless. Energy wise, the 300 wins to 900 or so, and the 7mm past that.
Right now, my 300WM is great. Its killed p dogs past 1k, and paper at 9/10 of a mile. Ive shot enough stuff between 1350 and 1575 do decide that id have no problem with killing power at 1500 if I can get the bullet in the right place.
That being said, a 7stw reamer lays on the desk nest to the computer mouse, and where 220SMKs have flown, 180Bergers and 176 Cauteruccios will fly soon.