Over the years in the Marvel Universe Galactus has been getting less and less “omnipotent” and godlike and Owen Reese, in his relative few appearances as the Molecule Man, has risen to the effective status of a Super God potency-wise with his Beyonder Universe/Cosmic Cube derived power.
In his most recent appearance in Dark Avengers, Owen Reese admits his power only works at a local range. Also, there is some doubt as to whether Galactus is composed of matter (molecules) or energy. Reese could damage part of his armor, but that’s about it. My money is on Galactus.
Galactus wins. Reece has been defeated Klaw due to his mental reservations and lack of confidence, which Galactus doesn’t suffer from. I still remember reading Thor when Loki thought Galactus was a joke and Odin seemed all-powerful.
Well, that’s either a retcon or he’s using an odd definition of local; he once restored a galaxy that the Beyonder destroyed. Also, despite the name he can handle energy just fine.
As for who would win, I regard it as a toss up. Galactus’s power varies wildly depending on how recently and how much he’s eaten; if Galactus was at his weakest Reese would stomp him like a bug. On the other hand, like Jormungandr Reese has confidence and other mental issues. And his powers depend heavily on that; his earliest version couldn’t handle energy because he didn’t think he could. If Galactus the Space God shows up, fully fed and ready to smash galaxies and announces his intention to squash Reese, it’s entirely possible that Reese’s lack of confidence will be his undoing.
Molecule Man was once famously outwitted by Tigra. Galactus is way more imaginative than either of them. Whether it’s just one character’s powers against another’s or all the resources they bring to the table brought into consideration, Molecule Man is going down.
Molecule man is only as powerful as he allows himself to be. As already stated he has issues. He once admitted to Kubik that he subconsiously used to convince himself he could not control organic matter. After he ripped the Beyonder from Kosmos and beat him to a pulp. Kubik stated that his origins as a mortal make Molecule man more powerful then himself or the Beyonder. (post retcon)
So all his limitations are realy his own doing. Due to issues. He realy liked going to therapy. He even once kidnapped Doc Samson to get a consultation.
But even at his most pathetic and winiest he still was able to come back from the dead after his body was destroyed. Making a new body for himself, once he figured out how, and a few minutes later beating up the Silver Surfer. Eventhough back then he was still convinced that his power could not affect organic molecules.
My guess is his issues are because he had a bad childhood and after he became omnipotent he did not ascend to become a cosmic beeing but rather chose to stay human. With all the issues that come with that. So it depends on what mood he is in if he would throw down with Galactus. In his most confident state I say he would put Galactus over his knee and give him a cosmic spanking for making him miss Sesamestreet or The A-Team reruns. (He likes those.) If Galactus would find him now like he is in Dark Avengers…well…Galactus must be pretty hungry if he would risk pissing Owen off enough to draw out his Darkest Aspect. But still Big G would have good chance.