Ninjitsu > MMA
Hands down. Not even close.
Reasons:
You can't see us; we can see you. You can't hit what you can't see ;)
We have weapons. You guys only wear tight shorts
Ninja outfits were created to make us harder to dox online
We can make you involuntarily shit your pants before the fight starts
There's no movies or video games about MMA guys going on an adventure. There's no "MMA Gaiden"
MMA isn't even real. It's just stolen from other martial arts