I'm kind of jumping around in this project to do all the 'interesting' conferences (which is to say the major conferences where the alignment I'm putting things in didn't exist in 1990) first, and today's entry is an old school / new school hybrid from the plains and mountain west.
When the eastern members of the Pac 16 and the western members of the Big 10 superconference were asked to leave, Nebraska and Colorado tried to recreate the old Big 8, bringing in some of their former conference partners who had been shunted off to lower-tier conferences in the super-conference era. However, the Oklahoma schools chose to join the Texas-based SWC instead. This required expansion further westward, and since Utah had also been forced out of the Pac 16, they were eager to join what looked to be an upper-tier conference, if just barely. Bringing in Boise State and BYU meant the northern plains and mountain west became the home of this new conference.
League Name: Making it clear that this conference owes its heritage to the Big 8, but is not the Big 8 -- and that they had no intention of keeping numerically inaccurate names -- this conference adopted the never-used-before moniker of the Big 9.
Members: Boise State, BYU, Colorado, Iowa State, Kansas, Kansas State, Missouri, Nebraska, and Utah
Advantages: Elite football power Nebraska and elite basketball power Kansas make this conference home. Utah-BYU is not a rivalry, it is a feud. Boise State football has been great since moving to FBS. While KC, St. Louis, Denver, and SLC aren't top-10 media markets, they are pretty solid. Utah and Colorado are growing markets.
Disadvantages: Only the downsized SEC has fewer people living in its home states of the major conferences. Rather spread out east-west (though all teams are in Central or Mountain time zones). No major recruiting hotbeds in-area. No one other than Kansas has had consistent basketball success.
Summary: While in many ways this conference harkens back to the Big 8, its future is in its 'new' members in the west. May have some trouble remaining in the top tier, but should be fun to watch.