I think the PSP is quite a sucess. It has sold more than all but 6 systems ever made. It offers a great library of quality games at very cheap prices now days (many are cheaper than $9.99 used). The system itself is now only $129 new. And is presently a very functional device for 2004 technology.
I think the PSP2 may be the best system for core gamers yet! (I has high hopes O.O )