Interesting. I came to the forum to look for an answer to the exact same question.
Short answer- Do it! I have one and love it.
Long answer-
1. Survivability- I would argue every bit as good as Invuln for regular S/L content. While Invuln can easily cap s/l resist. Electric comes in around 85% (basically the same as Invuln). Invuln may be able to cap energy/neg defense but Elec can cap Energy Resist and achieve decent negative resist. Not to mention Fire, Cold, Psi resist are all around 60% (much better than invuln). Invuln can achieve higher levels of hitpoints but Elec can regen faster plus endurance drain attackers...they get the job done differently but I really think it is a wash on most content. Caveat being sappers or Psi content. In those two cases Electric is clearly better. Also, since there is a ton of energy and psi content in the incarnate content, I feel electric armor is better than Invuln for new endgame content. The reason I am benchmarking invuln is b/c I love Invlun so much that my main badgers are invuln/dm tank and dm/invuln scrapper and brute. More and more I am enjoying the electric armor tank above my main toon the invuln/dm tank. I am not going to say to much about the -to hit effects/siphon life heal from DM....that is a pretty obvious advantage of this secondary set.
2. Damage- The damage aura does help. There is no question DM is single target focused. On my build, I picked up Mu Mastery to gain 2 AOE attacks. With these 2 attacks, my damage aura and incarnate nuke I don't feel like I am missing anything AOE wise.
My numbers with IO's-
45% S/L - Defense
33% Energy/Neg - Defense
27% Ranged
86% S/L Resist (just ~4% less than Invuln)
64% Fire/Cold Resist (can do those fire farms no problem if I need some rare salvage for recipe)
90% Energy Resist
48% Neg Resist
60% Psi Resist
Regen Rate 416% (Before Rebirth)
2467 Hitpoints
Compare those numbers to any other tank build you have and see what you think.
Good luck.
Has anyone created a character with this combo all the way to 50?
If so...how is it overall?
Does the damage aura help out with the lack of AoE?
What about the survivability?