SSJ4 VS SSJG

[Toriyama-sama]

Well, in my book Majin Boo is the villain. Gotenks-Boo and Gohan-Boo are just Majin Boo after having absorbed the Z Fighters. It's the villain plus something else.

But this isn't even to say base GT Goku was weaker than Gohan-Boo. We simply don't know. What we know is that base GT Goku is stronger than base Rildo, who is himself stronger than Majin Boo. Which Boo was Goku referring to, though, we do not know, and I take it as being Pure Boo (because he is the true Majin Boo ). But then again, that still doesn't say anything about the other forms of Boo.

[KentalSSJ6]

Considering that Goku has trained with what is the human version of Kid Buu for I believe 5 years (or is it 10 when GT comes around) constantly with both of them only getting stronger and able to further push themselves and if we take the Rildo statement seriously, id say by the arrival of GT, Goku has at least doubled his power since the fight with Kid Buu.

Pretty much Base and/or SSJ GT Goku surpasses End of Z SSJ3 Goku.

[Barunks]

I've always considered Super Saiyan God to be just another "in between" form much like the various levels of super saiyan in between 1 and 2. As such I assume just like all the other in between forms that it is vastly more powerful than the officially numbered form that precedes it (in this case SSJ3) but absolute kid stuff compared to the officially numbered form that comes after it (SSJ4).