Best thing Sefo has going for him is his ability to function in a pro-style offense. Plenty of I-formation, aces, under center formations, so he'll be well-equipped to handle the system. Many quarterbacks who've spent most their time in spread always have an adjustment period.
Liufau is most impressive on the run. His maneuverability makes him a difficult cover for opposing defenses to account for him, and he somehow always manages to make a play. When defenses seem ready to blow up a play in the backfield, Liufau manages to either (a) scramble for yardage, or (b) move from sideline to sideline to see if target opens up for him to attack. In fact a lot of Liufau's best plays in the pocket come off of designed half rollouts or bootlegs and hitting his receivers in stride to catch defenses off guard.
Liufau's mobility figures to be a huge asset for him in the Pac-12, particularly if he sticks with his Colorado commitment. It's easy to see why the Buffs like him--even if they're still rebuilding when he gets there, his athleticism can grab them some big victories.
Other notes:
Jon Woods of Ralphie Report gets this quote from Rivals:
Liufau was named his league's offensive MVP last season.
"And with the football aspect, they run a similar offense to what we run at my high school. I sat in on a few quarterback meetings and the concepts and terminology is similar. That definitely helped because a pro-style offense is what I want to run in college. I really like the offense, the balance and versatility that it has."
Kyle Rancourt, SB Nation Seattle:
Liufau plays in an offense that isn't exactly pass happy, but still puts up very nice numbers. He excels in the short-to-medium passing range, but can get a little erratic when it comes to throwing deep. He has the arm strength but hasn't quite mastered the accuracy that far down field.