If I had to pick one that I was allowed to use it would definitely be Ice Blast. I'm a controller at heart and love the mitigation it provides. A /Ice defender can play a lot like a controller.
That being said, a sapper character using Elec Blast is something I always meant to get around to, and perhaps will one day. I just feel the set really suffers from the lack of a strong third ST attack.
I believe that is because its specialty is supposed to be end drain.. and it has a pseudo pet.. Electric does well when paired with /Elec, /Nrg, /Mental which all can help its end drain abilities in different ways..
and if yow want to talk about being a mini controller.. E3's Elec/Elec/Elec can seriously lock down single targets if they chose too..
In the end my E3 did well and really shined when Incarante abilities came around..
However that being said.. I believe Elec is quite a bit more dependent on what secondary you chose to maximize its ability..
Ice not nearly so much affected..