For my Elec/TW Tanker I went with Agility Core: getting Power Sink to recharge faster AND give more end, even with only one enemy in range, probably helps my endurance management even better than Cardiac would.
Not getting the higher resists from Cardiac was a pity, but considering I can now drain end better and faster AND, if needed, get Energize to recharge faster makes me think I probably ended up with more mitigation than if I just had gone for the higher resists... The extra little bit of defense is just gravy.
And I did get better resists/defenses by going Barrier for my Destiny. Energize coming back fast on top of my other layers of mitigation (sapping, kd from TW, defense and resist), takes care of my healing/regen well enough. Barrier gives me some moments of silly indestructibilty AND shores up some holes in my defense and resist layers, particularly toxic damage (UG DE bosses, I'm looking at you!)...
I miss being able to bring people who get fisted by Marauder back to full health, though...
Playing CoH with Gestures
I went Spiritual Core on my TW/Elec Brute, mostly for the +rchg with a touch of +healing for energize.
Agility Core would be the next best thing. Enhancing your recharge slightly less than Spiritual, but also enhancing Defense and Endmod, both of which can be useful for an electric armor brute. +Rchg is still the main focus and reason to go either Spiritual or Agility and should be considered before the other aspects of either alpha power.
Energize (and to a lesser extent, Power Sink) Diminish the value of Cardiac and Vigor, even for an extremely end heavy set like TW.
Musculature is a poor choice due to the aforementioned low damage modifier of Brutes.
So I'm rapidly closing on 50 with my TW/Elec brute and I am just not sure what to do for his alpha. It's a s/l sofcapped build (well, 40% s/l right now) that has just a touch of recharge worked in where it can.
Cardiac obviously helps TW, but elec already has endurance tools so I'm not sure that would be needed. The damage resist to be had here could be handy, but is a bit underwhelming.
Musculature is going to give a nice damage bump, but that's it. Since brutes have lower base damage the impact to be had there isn't as pressing and the secondary effects there are nothing worth noting.
Resilient is the same issue, nice resists but the secondary effects are just not even worth looking at. Same issue for spiritual. I think the recharge bonus would probably be a better DPS bump than musculature for me though.
Vigor is useful, but lackluster. Nothing there to wow me, the heal is nice, the end redux is nice the acc is nice... but nothing just jumps out.
Agility is currently the front runner in my mind. The end mod stuff would be handy since it will affect my epic pool as well as stamina and endurance drain. This also gives the recharge I think would be a big dps boost, a little defense love (but not much since it won't affect set bonuses) and some move speed is always good.
Also.... trying to decide between barrier and rebirth. I think that with layered s/l defense and resists barrier might be less of a survivability increase. The things that are going to be dangerous are going to be mostly hitting things that are so neglected barrier can't fix the hole.
I'm not really well versed in high end brute builds or incarnate stuff however, so while I think I'm heading in the right way it's very possible I've missed something and any input is very welcome.