I went from turbo (petrol) Volvo to 1.4 Fiesta as my daily driver. With hindsight, much depends what you chose: In my case, although the Fiesta is a decent car (previouys model to the one you're thinking about) the fuel consumption is a bit crap and only a few mpg better than the Volvo which had over twice the BHP. Insurance and RFL not markedly different.

So, I'd suggest doing your research first, then decide. The new Fiesta is a very good car. Corsa.....less so!!