Depends on whether they're fighting you, each other or AI humans. Fighting you (I'm level 30, but haven't played Point Lookout DLC yet), the ghoul reaver and albino scorpion are tough to take down. Fighting each other unarmed--the deathclaw wins. Armed--the superbehemoth with a fire hydrant wins. Fighting groups of humans? Situational factors and strategic factors come into play. Humans e.g. raiders, brothers of steel, enclave etc win or live longer if they have higher damage resistance, powerful weapons and most important of all are able to use the advantage of numbers to apply "flank fire" i.e. surround and simultaneously/collectively apply firepower quickly to the creature before 1) it gets into attack range and position and 2) they (with their low damage resistance) all get taken out.

I tested the following using the PC console to set up "showdown at the ok coral/UFC " scenarios. Against each other with unaided with weapons, the deathclaw owns big time i.e. it won all its "fights". I was surprised to see how the albino radscorpion (which has a huge amount of hit points) go down relatively easy to the death claw's devastating strikes.

With weapons, the superbehemoth with a fire hydrant wins easy, all the time, one swipe = one kill. That hard to put down albino radscorpion even with your terrible shotgun amped up on psycho and ultra-jet in VATS? One SPLAT with the fire hydrant does the job easy. Ghoul reavers and deathclaws go down even easier.

Another scenario I tried was how each creature would fare against groups of humans e.g. raiders, brother of steel, enclave soldiers, slavers etc? This is what I found. If a deathclaw is surrounded it will die quickly because with limited hit points it will take too much damage from "flank fire" before it is able to kill each raider/soldier/slaver.

Line the individuals up in a row so they can't concentrate their fire (as a group) on the death claw before the death claw gets within contact range? The humans become easy pickings. The death claw with its lightening speed and devastating claws will kill everyone before anyone is able to fire a shot.

The albino radscorpion, ghoul reaver and the superbehemoth can take waves of damage from human-fired weapons (bar the most powerful ones eg alien weapon) but not indefinitely. If they take too much fire, they will die before they're able to eliminate all members of the human-based group.

Based on my "findings" it's a coin toss between the albino radscorpion and the ghoul reaver to who is the strongest of the "flank fire" resistant creatures.

I let loose a deathclaw in all of the following; Citadel, Fort Independence (and Fairfax Ruins), Paradise Falls to see which were the toughest humans as a group. Could they kill the beast before they were all eliminated? The deathclaw cleaned up the brothers of steel and the brothers outcast but not the slavers. Those tough slavers are frigging tough. They killed the deathclaw in all of the 5 scenarios I ran--with at least two or three slavers still alive after the fight. Note, I only used one deathclaw. Using two was overkill i.e. they cleaned up any and all location easy.

I hope my "experiment findings" answer your question.

The creature I'm most impressed with? The deathclaw. Not against you the player but against other AI creatures and humans. Its speed and deadly "samurai sword"-like claws more than make up for its low hit points. In general, this makes the deathclaw absolutely devastating against other creatures and humans in the game. A beauty to watch in full-flight and kill-action.