Cutler has the higher ceiling, but also the lower floor.
Ponder will get you a consistently mediocre alex smith like day on a week to week basis. I dont think he ever goes off for huge games, but wont have a 3 or 4 interception game either.
Cutler on the other hand has the potential to go off for 350 and 4 td, but on the flip side, he could also end up with 180, 1td, and 4 int
I would go with Cutler personally, but ponder might be the "safer" pick