I have both consoles (just bought a NDSL haha)

What i feel so far is, PSP is very good at shooter games, RPG and uhm tekken that kinda games while NDSL is more to cute cute games which don't take much out of your brain. =P (which suits the very lazy me)

Sometimes PSP can get a little overwhelming and its not something to play on a short bus trip. NDSL suits that.

But i guess ultimately one should choose the console depending on the types of games desired. For me.......

I bought NDSL cos i wanna play Pokemon =X