Really, it does come down to personal preference. With electrics you have the cost of the motor, batteries to be in the plane, ESC (the 'throttle' for the motor), and extra batteries or field charger. With fuel powered engine you have the cost of the engine, fuel, fueling and starting equipment, glow or spark plugs, servo for the throttle, and extra batteries or field charger. Ya pays your money and ya makes your choice.
Fuel engines need maintenance and occasionally parts. Electric motors need some maintenance as well, and battery packs do not last forever.
As Hydro Junkie pointed out, noise is also a factor. Will you be at a club field where noise is accepted or in a park where it is not. When it's all said and done, it's up to the modeler to choose what is right for his or her needs, and noone else can make that choice.