Is the PSP considered successful for Sony?

[Bursche]

Yes it is successful, in the same way the Xbox was successful. It broke into a market that was otherwise monopolized and took some marketshare and set the foundation for future consoles. While it is obviously not the winner, it has so far been the best competitor against Nintendo in handhelds.

As long as Sony doesnt try to push another format with their next one, UMD's FTL!, they are only going to grow.