hurm..i hve both handheld.

i prefer psp than ndsl

nds was fun but i dunno..nds games cn get boring fast,the screen was small
the best game i played for ds is trauma center1,2.spiderman 3

if u hve psp and u are pes/we fans..u can enjoy psp for really a long time
and resistance psp can do something with ps3 if im not mistaken
gta psp also ..urm better than nds