Electric or Gas water heater?

I can only say that with the electric payment structure in Spain, the larger the water boiler the higher the potencia requirement which increases your monthly billing for the electric.

If you can keep your potencia low in spain your elec bills will be lower too

We've minimised our electric bills as much as possible . Talking to neighbour the other day and his bills are much less and he's sure it's because he has gas water heater.  However, before we go to expense of changing I was looking for some opinions, maybe some people have changed over already. 

From what I have seen i believe it would be cheaper on gas.

If your boiler is more than 8-10 yrs old than no matter which you change it to it would cost less.