My first inclination is not much. At the top of the league you have Oklahoma and Baylor at 3-0. West Virginia is right behind at 2-0. Oklahoma was the preseason favorite, Baylor was a pick near the top by most, and the Mountaineers were my surprise team in the league. Oddly enough, two of the leaders wins came against the same teams as Oklahoma and West Virginia both have beaten Kansas State and TCU.
Oklahoma's remaining schedule has these possible challenges, Baylor in Norman on Nov. 12, at West Virginia on Nov. 19, and then at home with rival Oklahoma State on Dec. 3. West Virginia has TCU in Morgantown this week, at Oklahoma State on Oct. 29, at Texas on Nov. 12, the game hosting OU on Nov. 19, and a date at home with Baylor on Dec. 3. Baylor still has Texas on the road Oct. 29, hosting TCU on Nov. 5, Nov. 15 they go to OU, K-State in Waco on Nov. 19, and at West Virginia on Dec. 3.
Outside of those three, Oklahoma State at 2-1 in Big 12 play and TCU, in my opinion the best 1-2 team out of a group that includes Texas, Texas Tech, and Kansas State. K-State might be the other school out of that group that could muster the effort needed to fight it out but the Wildcats have road games at Baylor and TCU. Oklahoma State has to go to Kansas State, TCU, and Oklahoma in November which will be tough.
Oklahoma is playing the best of any team right now, but its spotty defense leaves them open to be upset. West Virginia is better defensively but not quite as explosive on the offense side, especially in the passing game. Baylor is really solid on both sides at times, but also can come up inconsistent at times. TCU has been Jekyll and Hyde, especially on the defensive side. Oklahoma State has shown quarters, even halves of being really stout, but has also been inconsistent.
What it proves is something that I'm becoming to believe exists across the country with the exception of only a few teams such as Alabama, Ohio State, and maybe a few others but I'm not convinced enough to name them. Look at the Houston win over Tulsa 38-31. Tulsa nearly tied that game up at the end. North Carolina State takes Clemson to overtime and with a more mentally strong kicker it would have been over with a late field goal and Clemson would be blemished. Duke came so close to getting Louisville on Friday night. It happens every week. There really isn't much difference between teams outside of a few.
November in the Big 12 should be a lot of fun. If I had to pick the Big 12, I'd go like this:
1. Oklahoma, 8-1
2. (tie) Baylor, 7-2
2. (tie) Oklahoma State, 7-2
2. (tie) West Virginia, 7-2