KNOW IT ALL brung it up....for some reason...
then skirm tagged along...
I don't tag along, I brought up a valid point and discussed alternatives.
Nesh can even tell you that Brolly is no stronger than a SSJ2, which based on what Cell was claiming was no more than a System Buster. So then if Brolly < Cell then how could he have Busted a Galaxy. This and the fact it doesn't fit the timeline means that it is Non-Canon to the main series, and cannot be used to accurately gauge a main cannon characters power.
But still, Goku as SSJ3 would have been able to beat Buu (if he didn't mess around)
who was confirmed in non-filler as a Galaxy Buster, the first and only Canon Galaxy Buster in DBZ too. Since DBZ places no actual separation between Power to Destroy a Galaxy and the Power of a Person then SSJ3 Goku was Galaxy Buster.
So if SSJ3 Goku = Galaxy Buster
And OF Thor = Galaxy Buster
Then it's equal based on Strength alone... but Goku has an edge. He has his entire Life's Experience fighting Super Powered foes who at times were much more powerful than he was in battle. As well as his Martial Arts which he has practiced throughout his life of Training and Battle. As well as the fact that all of his considerable intelligence is put into being Battle Smart, which leads him to look like an idiot when not in battle...
IMO Another edge is that I believe that Ki attacks would prove the Better Weapon than Thor's Hammer. With the Hammer you can only do so much in this fight, but Ki is varied in it's use. It can be used to amplify Goku's power, or create invisible attacks, create disks of energy that can slice through ANYTHING, Lens the Sunlight to produce a Blinding Flair of light, move instantly from one location to another, all in addition to just throwing it at people in a Beam or Ball. (there are still more techniques of using Ki out there that are different, but these are the ones Goku knows)
Goku wins by having equal power, better experience & training, battle smarts, and a better weapons than Thor.