King Cosmos wrote:At most, Mystic SSJ is equal to that of SSJ3. Keep in mind you are comparing Gotenks SSJ3 and not Goku SSJ3.
WTH is Mystic SSJ? After getting the Mystic powerup, Gohan doesn't go SSJ, unless you count the craptacular Dragonball GT which IS NOT CANON!
Second, it's hard to tell who is stronger between SSJ3 Goku and Mystic Gohan. General fan concensus states that Mystic Gohan is stronger, by the argument Mystic Gohan > Super Buu > Kid Buu > SSJ3 Goku. Personally, I think that Kid Buu > Super Buu, making it a bit harder to tell. However, he can definetly outlast Goku.