SEC is still better top to bottom simply because of one thing... toughness... pound for pound, even the bottom teams are tougher than the Big XII's bottom teams...
At the top... you have OU and Mizzou, who would match up really really well with Bama and LSU... then Texas and OSU seem to line up with UGA and Auburn...
It's getting closer, but the SEC is still better in my opinion... and I'm a Big XII guy...