EU Fett has this by a mile. Since I don't believe in all that EU mumbo jumbo, I'm going to base my verdict on the films. Boba Fett is the best mercernary money can buy. He's hired by Darth Vader, Jabba The Hutt, and just about anyone who can meet his price. Darth Vader allows Fett to talk shit to him. He even offers him compensation for Solo if the carbon freezing process killed the smuggler. To me that speaks volumes about his skills. His armor is obviously insanely durable. Look at the dings from what can only be assumed to be shots from blasters or other projectiles. He was caught in the blast from a mounted laser cannon and was just knocked out. He's armed to the teeth. Aside from his normal blaster, he has the following weapons: a flamethrower, wrist rockets, knee darts, a missile launcher in his jetpack, gauntlet blades, wrist lasers, a whipchord, and that's just the shit we can see.
The Super Predator is insanely powerful. He has a minigun style blaster on his shoulder and can launch his blade as a projectile. As far as armor goes, he doesn't have a whole helluva lot. His vitals aren't even covered.
If this comes down to melee, Fett will naturally be at a disadvantage. It's likely that the Predator will be able to knock him around and possibly slash his unprotected areas with his blade. Fett has blades of his own of course, and is extremely quick and deliberate in his movements. Even with a serious size/weight advantage, Mr. Black will have a hard time killing Fett. And that blade will do nothing at all to the Mandalorian armor.
At mid range, the bounty hunter has this. That flamethrower will end the fight before it begins. There's no evidence that the shoulder blaster is any more powerful than a blaster. Fett's armor givers him all the advantage that he needs, and his weapons will tear the giant hunter up faster than vice versa. Obviously, a few things could go wrong here. Fett's jetpack could be hit. Or there's the off chance that Mr. Black will hit his neck or another unarmored part of his body with the blaster or the blade.
All in all I'm sure that there will be some dreadlocks to match the Wookie scalps on Fett's shoulder, 8/10.