depends on budget.
sabertooth - looks, TUF components, generally last generations ROG innovations, some fans to "cool" the board
Formula - expensive, watercooling option, ROG armor, soundcard, oc panel port, ROG connect, LEDs on it, supposedly a "better" overclocker (but the OCing myth disproved by Linus and TTL, OCing is moslty chip dependent not mobo)
if you want the ROG features, get the hero board. if you want the clean armor look get the sabertooth, if you want the watercooling and sleek looks, get formula, but all of these are, TBH overpriced compared to some other boards like the MSIs gaming g45