I have an EM/Invul and it was fun for me until I got past 40. I run solo or in small teams. I think it is a combination between EM endurance and Invul not having any power to recover endurance. I got her to 50 but rarely play her now. I run with at least one endurance reduction in each power and have stamina.
I would look for sets that give +max endurance as well as the accolades.