TFF is very much like TOS with its focus on the "Big Three" and its Humanistic values. It's also a lot like a specific TOS episode, "the way to eden."
I'm surprised folks would say TMP. Other than the basic plotline ripped from "the changeling," the rest is nothing like TOS. Where TOS was fast-paced with characters like family, TMP is glacially-paced, with cold, distant characters replacing the ones in TOS. It's also much more dependent on special effects than TOS ever was.