Well there are 3 Key Points which need to be considered when thinking about your heating.
Efficiency:- An energy efficient heater which produces radiant heat is better than a heater that produces mainly hot air.
Controllability:- A heater that only produces heat when its required by you ie. Thermostatic and time controlled
Tariff . The cost of your electricity, shop around for the best deals. If on THTC remember you CANT change supplier. But if you are changing your heating and going onto a standard tariff then try this site for cost comparisons www.moneysavingexpert.com/cheapenergyclub