Top Tier:
BYU - Royal just pops like no other.
UCF - Very clean home or road unis
WV - Love the color combo. Definitely pops!
OSU - I just like the color combo, and love the gray alternate
Colorado - Love the colors and the iconic buff helmet.

Good:
ASU - Really solid color combo and logo!

Meh:
KSU - Purple just doesn't do it for me. It's OK in an all-white, but otherwise - meh.
Utah - Just so, so average. Helmet logo is cool, but otherwise - meh.
Cincy - Just very meh on every level
Arizona - Red, white, and blue just has too much going on.
Houston - See Utah above
TCU - Their road unis can look clean, but their home unis are not.
Texas Tech - See Cincy above

Ugly:
Kansas - Red and blue just clashes. Negative points for having a Looney-Tunes mascot on the helmet.
Iowa St. - Maroon and yellow just doesn't pop. Looks dirty.
Baylor - Gold and green is just an ugly combo no matter how you try to clean it up. IMO the ugliest unis in the league.