I just read an article comparing the differences between the CBR and the Ninja 250's. While the CBR seems to be a pretty good bike, the Ninja does offer two cylinders compared to the CBR one, so the Ninja can outrun the CBR. Styling in my opinion also goes to the Ninja. If I were to consider to get anything besides the Ninja, it would be the Hyosung GTR250R. But again thats just my opninion. Also I think 2600 for a mint condition '08 would be a pretty good deal, maybe try to get a little shaved off.
'09 Ninja 250