In reality though, with set bonuses and Incarnates, from my own experience, I put Electric Number one.
Once it has high defenses to all positional damage and is capped for Energy and S/L and nearly capped to all except Negative (70 or so) and Toxic (50ish), Electric barely gets scratched with most content. The heal is barely needed. Add to that that all the end drain and Psi damage you see in the late game that doesn't even phase electric, and you have a Tank with no real holes and is nearly unkillable. I almost said Is unkillable... but you may occasionally see the floor like any Tank does, once in a blue moon. \
Oh, and how hard do mobs hit with their endurance floored and kept there? Not very. lol
That is my story and I am sticking to it. And yes, without IO's and Incarnates, Elec is mid range. And playing it to 50 can be a challenge at times compared to say Bio. But later, it's crazy godmode like! Power Surge is laughable, because the tank is already at higher numbers, with no crash after 3 minutes. 😉