Let's compare the different monsters and see how strong they are!
GFW Hedorah: No acidic qualities, wasn't immune to thermonuclear breath.
Showa Hedorah: Disolved people almost instantly into skeletons. Was immortal basicly, if there was a water source around, he would never dry out. Almost killed Godzilla multiple times via: Choking, Smothering, and Melting. Messed with Showa Godzilla's regeneration so bad his hand remained skeletal through out the fight.
GFW Kamacuras: Was able to withstand missiles hitting his back, but was impaled by a radio tower?
Showa Kamacuras: Was able to go toe to toe with Godzilla, and one was able to survive getting hit in the face with Godzilla's heat beam multiple times.
GFW Kumonga: Ignoring the fact he somehow JET PROPELLED HIMSELF BACKWARDS after Godzilla threw him, pretty much the same as...wait, no.
Showa Kumonga: Was venomus, almost killed Godzilla twice if Minya didn't step in and stop him.
GFW Rodan: After being hit by Anguirus, he fell into a nose dive, which he could easily have pulled out of, but no, he just spiraled downwards while screaming like a loony. Was knocked out by a mountain.
Showa Rodan: Was able to ram himself, top speed, into Ghidorah, both falling with Ghidorah basicly landing on him, and get back up to fight.
GFW Anguirus: While in the Thunder Ball mode, an offensive AND deffensive move, was knocked out by rolling off Godzilla's chest into a mountain.
Showa Anguirus: Survived falling into a giant crater in Megalon, a buzzsaw to the face and getting dropped from a good distance in the sky in vs Gigan, survived a beating from MechaGodzilla, and was dropped again, onto his back, and then stomped on, by Ghidorah.
GFW King Caesar: Was slowly tossed into a mountain. And boy, let me tell you. I've had arguements with a guy on TohoKingdom who thought the act of Godzilla merely tossing K.C was enough to knock him out.
Showa K.C: Was able to get back up after a beat down by MechaGodzilla, then again after MechaGodzilla used his all out attack.
GFW Gigan: Not so much weak as he is stupid. He was dumb enough to stand RIGHT infront of the working end of Godzilla while reeling him in towards the chain saw belly.
Showa Gigan: Fought Godzilla three times, and was beaten to retreat. Constantly shot down out of the sky. Was finally killed by Zone Fighter.
Now we get to the fun one:
GFW Godzilla: Yeah, his skills were impressive. But we've seen them all before in OTHER forms of Godzilla. I take it you all saw the Godzilla vs Gamera death match by ScrewAttack, correct? I don't need to get into the whole 'meteor' thing right? We've all seen it.
Showa Godzilla: Was able to achieve flight with his beam. Watch the Deathmatch again, they go into detail about how this could have happened.
But not just that, Godzilla has thrown kaiju heavier than him around like ragdolls. Ghidorah, Hedorah, and MechaGodzilla 2. He was also able to dismember monsters, (Ebirah, Spyler, Jellar) easily. He is smart enough to know human fighting styles (Boxing, wrestling, karate). as well as know when to team up with other monsters to face a bigger threat. He was able to survive Hedorah. That alone should make him stand out.
He used his tail alone to lift and throw Gigan around multiple times.
Heisei Godzilla: By far the STRONGEST Godzilla there is. Faced some strong opponents. Was able to lift MechaGodzilla II like he was a balloon by grabbing the most awkward part of the mech's body. Survived the fights with SpaceGodzilla and Destoroyah. That alone makes him VERY impressive. Not Hedorah level, but seeing as the one who fought original Hedorah was only half of Heisei's size...
Final Wars Godzilla suffers from 'weaker monsters make me look good' syndrome that GMK Godzilla suffered before him. Am I saying he's a weak baby? No, that honor belongs to the 1954 Godzilla, who was afraid of planes. GFW Godzilla is somewhere between Showa and Heisei. There's other Godzillas that are on that scale, but really, comparing any other Godzilla to Marvel's is stupid, since that one took Mjolneer to the face and got up like it was nothing.