Well modern SNK fighters (mainly KOF) are definitely played differently than SF.
Sure there are some tactics from SF that are applicable but overall KOF/SNK are more rushdown, jump games, extremely agile/mobile oriented.
I would reccomend watch a bunch of VS matches on youtube, but first try to get a basic understanding by watching some tutorial videos posted in the KOF strategy section on the main forum index page.
Also, the official strategy guide for KOF XII is very helpful for new players and veterans alike. One of the writers is a member here.
And if you have Xbox 360, get NGBC HD remix coming out soon for Live Arcade, that game plays more similarly to SF than other modern SNK fighters.
But it will also help you transition to KOF.
It’s being discussed here :