Elec Blast used to be very weak, but an update greatly improved it.
If you plan to use it as pure range, you will seriously gimp your toon. The reason is that one of Elec's great abilities is draining endurance. This will weaken your opponents. Of course, this is only useful if you drain them entirely. I don't know if this is true or not but someone told me that you get a large dmg bonus after you drain all of their end.
Short Circuit from Elec Blast and Power Sink from Elec Manip are your two main drainers and they are both PBAOE. I run in quickly and hit them with both and then run a distance and hit them with distance attacks. Most other Elec attacks also drain, but not much.
I don't always do this. Sometimes I just distance attack, especially if it is just a bunch of weak trash mobs that won't last long.
I prefer Elec/Elec. Some people prefer Elec/Energy because Power Boost will greatly strengthen the End Drain.