If I were to rank them:
Z Goku - while getting progressively less caring and more prone to ridiculously risk-taking behavior later in Z, he at least makes the transition from a young man to a mentor character fairly well, not to mention his pure of heart schtick has less holes than his kid version. I'd still argue he degenerated as a character after the Freeza arc, as if that heart virus took away half of what was human in him
He also gets some points for accepting his Saiyan heritage despite nasty run-ins with the other survivors and letting go of his desire to hog all the fights so the more promising younger generation can take charge, which is still handled terribly but at least it's something.
DB Galu (pre-23rd) - Overrated and lacking in justification for his morally shady behavior, particularly slaughtering people upon the simple mention of them being Red Ribbon. I'd still argue that his Piccolo Daimao arc self had better moments and sucked less as a character compared to his RRA self, but he still made such a rapid transition from the merciless fighter that openly announced he'd kill Daimao no matter what and popped Drum's head without hesitation, to the merciful Z self seen from Piccolo Jr. onwards that it was awful writing. Roshi also pretends he's always been like that too, although he at least has the excuse that he was never really educated and that all of his victims were technically villains.
GT/Super Galu - both regressions of a flawed but mature character by the end of the manga. I have no clue why Toei would have Goku behaving once again like a 12 year old that can't count to 20 when he's really over 50 just because his body was deaged, and this still makes it laughable how he becomes the Dub!Goku like Superman character when he's in a serious fight. Super!Goku, more of the same, except seemingly even dumber for no other reason than stereotypical writing (which I'm pretty sure Toriyama was at least partly to blame for when you consider that he's an idiot in the manga as well).
At the very least, he at least fights smarter considering he managed to pull that KKx10 shit which no one had once thought of whereas GT!Galu was literally able to sense ki from S17 and still fed him most of his energy for no fucking reason, holds back in base form for over half the fight and pulls a massive genkidama without even really needing to convince ppl etc.
