In the day I was a PJ, I needed the 1.4 and 2.0, for low light, I could not afford the really fast glass. In terms of performance the 2.8 is just as good if not better at 5.6 or 8, unless you need a low light lens I would go with the 2.8 and use the 250 for another lens like the 200 F4 or 28mm.