Brown has a much more extensive list of accomplishments at Texas than Bronco does at BYU:

1 National Championship (2005)
2 Big 12 Championships (2005, 2009)
6 Big 12 South Division Titles (1999, 2001–2002, 2005, 2008–2009)

Paul "Bear" Bryant Award (2005)
Bobby Dodd Coach of the Year Award (2008)
2x Big 12 Coach of the Year (2005, 2009)

(this one is huge) The Longhorns under Brown were 32-17 against their four archrivals: Texas A&M, Oklahoma, Arkansas and Texas Tech.

• 20 consecutive winning seasons
  
• 18 consecutive bowl game appearances
  
• 162 consecutive weeks ranked in the AP poll from 2000–2010 and 192 consecutive weeks ranked in the coach's poll from 1998–2010.[31]
  
• Big 12 Conference record 21 consecutive conference wins from 2004–2006.
  
• Player awards at Texas under Brown include a Heisman Trophy winner (Ricky Williams), three Maxwell Award winners (Ricky Williams, Vince Young, Colt McCoy), two Davey O'Brien Award Winners (Vince Young, Colt McCoy), two Doak Walker Award winners (Ricky Williams, Cedric Benson), a Butkus Award winner, two Thorpe Award winners and four national player of the year honors. Texas has also had 23 All-Americans, 37 first-team All-Big 12 selections, three Big 12 Offensive Players of the Year, two Big 12 Conference Defensive Players of the Year and seven Big 12 Freshman of the Year honorees.
  UT posted back-to-back 11-win seasons, nine consecutive 10-win seasons and ten consecutive 9-win campaigns for the first time in school history.
  
• The Longhorns under Brown featured the only 3,000-yard passer, the only 2,000-yard rusher, the only 1,000-yard receivers and the only 1,000-yard passer/rusher in UT history (again, note the longer seasons in recent decades).
  
• Brown is one of only three head coaches in FBS history to coach players who recorded a 2,000-yard rushing season, a 1,000-yard receiving season and a 3,000-yard passing season. Also, Vince Young stands as the first player in NCAA history to rush for 1,000 yards (1,050) and throw for 3,000 yards (3,036) in a single season.

there's a big difference. He won a National Championship, he cranked out winning seasons playing a much better schedule than MWC/WAC teams, he absolutely owned their rivals during his time. The sun sets on everyone, it was sad to see it set on Brown, he was a great coach for a long time and a classy guy.