What is the difference between SFAB and SF?

SF - unconventional warfare. Raising an army in a hostile country to over throw their oppressive government.
SFAB- Foreign Internal Defense. Training foreign troops to be (hopefully) competent soldiers.
SF can still conduct a whole spectrum of special operations, not just UW. SFAB as of right now is a conventional force. Trained as such. I have no experience with either, but I'm pretty confident others would back me up on this.

We get a Lot more money than SFAB.

I'm certain actual SFAB personnel can provide more depth than I can, but from what I've read...their mission is not all that dissimilar from the ETTs of the mid-2000s. As ETTs, our primary mission was advising the local national government armed forces. Some teams were maneuver units, advising on actual combat skills, and acting as enablers/force multipliers. Others, were more focused on garrison tasks and administration. Others still, worked primarily in engineering and infrastructure roles. To the best of my knowledge none of these were performing in the way an ODA would, nor were they routinely working with forces outside of the "official" LN military or law enforcement. Don't misunderstand, I knew some ETT personnel who were being drawn from some of the best...101st, 82nd, 10th Mountain, etc. We even had a Reservist who was a former SEAL on our team. By the very nature of how we were organized, there was a different "culture" than what I'd expect to find in any truly 'line' unit. However, in my personal assessment, the comparison is not close.