Both great in different ways!
I am a little confused! If the title of your argument says ALL-TIME, then why would you only take stats from a certain date? The Big Ten prides itself on its tradition, which dates back farther than any other. And not to include that in the stats is not fair to other schools, just because the SEC is younger and did not do as well in earlier years.
The Big Ten's success in the early years should be noted, along with the strong midwestern football tradition (Nebraska, Notre Dame, etc...) that has six out of the top seven schools in all-time wins. The Midwest has the deepest and richest football tradition (both football hall of fames, oldest and winningest teams in college and pro, and the most recognizable stadiums, uniforms, fight songs, etc...)
The SEC and the Big Ten, in my opinion, have the two best football conferences. The Big Ten is the oldest and has the most tradition, and the SEC has had an unparalleled amount of success in the past decade or two. If you look at conferences right now, the only two that are not freaking out are these two, because the SEC is dominating in football, and the Big Ten has too much tradition and high academic standards to worry about falling behind.
And for the last note, looking at bowl games is a bad method for grading programs and conferences. At the height of the Big Ten (and especially Michigan) we did not play in bowl games, and when we did, only one team out of the whole conference could play. The Big Ten did not want to travel that far during exams. Also, almost ALL of the bowl games are played in the south, mostly in Florida, Texas, Pasedena, and New Orleans, giving the home field advantage to the southern teams almost every time.
Don't get me wrong, I think the SEC is by far the best football conference from top to bottom right now, but when looking at ALL-TIME stats, you have to include ALL the stats, which makes the Big Ten a very respectable conference as well.