BYU held on after jumping out to a huge lead, but this is still a really good team even after losing key players from last season.  Jaren Hall's health is a question mark but Romney is a capable backup QB.
BYU's quietly put together a decent record so far, with wins over three Pac12 teams. Despite not many ranked teams left (right now), an undefeated season would be impressive for them.
I don't like how they let up on the gas against USF but the 3 P5 wins even if against the middle and the dregs of the Pac-12 still is impressive. They have a penchant for close games even against terrible teams like Arizona. which sours me on them a bit.
Forcing turnovers is covering up a lot of blemishes for BYU. They aren't that good on the lines -- they were outgained pretty badly on a per-play basis against both Utah and Arizona State -- and although their offense has some pop, they are super leaky at the back of the defense. Wins are wins, but I'm not sure how long they can keep getting away with it.