Currently, i am only playing Super Mario 3D Land ... its a fu""#$"$ awesome game!
Relating the 3D, i have never had headaches issues... i guess it depends from person to person, but i also read that the 3DS XL is more accurate in the 3D.
You can always turn the 3D offf .

Regarding the power, its not a PS Vita, but the are very, very pleasant...
Best regards