Up until the 30s, Willpower is going to have a lot better survivability. Then Electric starts to catch up. Electric gets a heal at 28 (Energize), and once you get Power Sink slotted you'll never have endurance issues again. Although Power Sink requires enemies to work, it is autohit, so it is very reliable (plus it gives you something useful to do while sitting through the reduced-damage time from Rage crash). Foot Stomp, from the knockdown, and Power Sink, from draining enemies of endurance, add a lot of miscellaneous survivability. Lightning Field not only adds much needed AE damage (Super Strength only gets Foot Stomp for AE and not until 32), but also lets you do low-level ambush missions in the Mission Architect if you want to speed level through the low levels (see the CEBR thread for more details), something SS/Willpower can't do. Even on SOs, by 36 you'll be very powerful and you'll only get better as you start investing in IO sets.
As for Patron Pools, Mu and Soul both make good choices. Mu gives you two AE attacks (Electric Fences and Ball Lightning), while Soul gives you Gloom, an amazing single target attack that you'll want to work into your standard rotation, and Dark Obliteration, a decent AE attack.
See title above.
Ok now for the details.
-I have a 50 EM/WP brute and I like him a lot.
-Endurance is a concern of mine.
-IO's are something I fool with if I have the time, salvage or inf. I never go out of my way to IO any character. In fact when giving your answer choose the best set that works with SO's but would benefit from basic IO's if I choose to. (I'm slowly working on adding 5/6 of crushing impact to my EM/WP, and I mean slowly)
And
-What epic/patron should I go with (assuming he gets to those levels)
I'm leaning towards /WP because I actually have experience with the set. Playing a melee without a heal component kind of makes me nervous because I've never done it before, even though I've seen some monstrous things done with non-healing armor sets.
And I really need to update my Sig, only 2 out of 6 of those characters still exist.
50Soulsunder: DM/Regen Scrapper
50Limitshift: EM/WP Brute
Victoria Nox: Dark/Dark Dominator
And about 5 others that change constantly...