You won't get an argument from me. I think it is universally acknowledged (or should be) that, at least the SEC West SOS is the most difficult by far. Alabama's schedule is brutal (SEC West foes and UGA and UT).
Still, I don't think there is any correlation to post-season success or lack thereof (also as you point out SOS really can't be determined until year-end). One year fans argue their battle tested favorite team is the champion because of a strong SOS and the next year it's an excuse for being "worn out" (after a 3-4 week layoff between last rivalry game and big bowl game).
Ohio State and Michigan State can play with any in the SEC West. No doubt about it. I'd say that Penn State, Wisconsin, and Minnesota this year are equals to the mid-tier SEC West, maybe a notch below depending on which team and how their season goes (Bama vs. Wisky might be a good gauge). Nebraska is a further notch down or maybe. Michigan is equivalent to UT - traditional power that is down with a new coach bringing excitement (given the Jones is in his third year, I'd put UT ahead of scUM at this point but not for long with Harbaugh, unless he gets committed to an insance asylum). Rutgers, Maryland, Iowa would be bottom dwellers in the SEC West and mid to lower in the SEC East (where R and Md are in the B1G East). Indiana, Illinois, Iowa, Northwestern are bottom dwellers (probably even in the ACC) and Purdue might be able to beat a good high school football team.