What was the greatest leap in power for handhelds?

[JoeTheBro]

thekitchensink said:
Just like with consoles, it was definitely the jump from 2D-focused systems to 3D-focused ones, whether you wanna say GBA to DS or GBA to PSP.

If that's the case, wouldn't it be from GB to GBA?

GBA had lots of 3D games:

(Yes they cheated a lot with sprites but still 3D)