PSP has been pretty successful it has not been the run away success that NDS has been but it can hold its own. Considering everyone in Japan and their mother have bought an NDS in multiple colors it is no surprise. I think it is actually amazing that they managed to sell as many as they have (there is just so much disposable income in a household).
PSP has some great games, NDS may have a few more however I am not convinced that it is a better handheld. It has just lowered everyone's expectations of what a handheld game should be. I wanted a console like experience where I could pause and resume my console at any time and PSP has provided that for me.
NDS has brought everyone's grand parents into the gaming fold and I think it is great. It has also increased the market for puzzle games which was lacking in previous gen.
Most mature games have come to PSP however I am hoping software makers would embrace PSP more and create more games for it.
PSP 4000 with a 3D screen would be awesome ;)
