Well that depends upon the size model you are flying. I fly both electric and glow and believe me, I have some electric models that will eat glow powered models for breakfast when it comes to outright speed and vertical climb. However they are small, hand launched models.

The one pictured below is an example and it handles wind speeds that many of my glow models cannot handle safely. It is a 3 channel model (the design is based on an 1/2A Texaco Pylon Racer) with 2 mini servo's and the 3rd channel an ESC. The motor, like the ESC, is an Asian made brushless outrunner and the battery pack is a 3 cell Lithium Polymer.

The total cost of the model and the neccessary gear to get it flying, was a lot cheaper than a reasonable quality, 4 channel, .46 sized ARF sport model.

One just has to shop around.

So basically you can fly electric quite cheaply, but the model will be small. Get used to that fact.

If you want to electrify a .46 sized glow model, yes, it will cost you quite a bit of money and personally I would not consider it. For models that size, britbat is right.

But as more and more excellent brushless electric motors and ESC's appear on the scene from Asia, prices are steadily falling and within the next 5 or so years, well, it may become an economical proposition.

There is one area though that electrics are cheaper than glow and that is in Ducted Fans. There are some great scale Electric Ducted Fan models around that are quite reasonably priced, especially when compared to their glow powered counterparts.