I had a Fiesta st and now have a megane. Overall my megane rides much better than the fiesta over bumpy surfaces and is far more compliant as a daily driver. My megane is a 275 however and I have never driven or been in a 250 so would not know the exact differences. If it was between a 250 and a fiesta st the choice would be much harder for me I think as the fiesta st would be alot newer and far cheaper to maintain specially with fords capped price servicing programme. Both cars are immense fun. Around town I feel the fiesta was slightly more fun as you could use more of the power more of the time and also the size of the car. Around the twisties however the megane is a completely different beast and is very enjoyable. You won't go wrong either choice. All comes down to how much you want to spend and the ongoing maintenance of the car.