A GTS 250 is:
An "Overclocked 8800 GT with 55nm technology and a brand new board design that's an inch and a half shorter than the 9800 GTX+".
And a 9800 GTX+ is:
An "Overclocked 8800 GT with 55nm technology".
Read the following to understand what your getting if your considering a GTS 250.
Regardless of the naming system complexities, the 1 GB version is still a great deal for under $150 if your buying a PCI-E Video card for the first time! Or especially for a PC with a smaller case! (Get one with a lifetime warranty.