Ageless T3 (the one that gives a 90sec buff) is really good and very noticable vs the 60 sec one. Definately give that a go, if you are struggling with end like I was on my brute I went for the Alpha slot with the +End/Reg/Def Boost. I plan to change that later on once I finish up my own slots (and gain more def/power accuracy and recover/regen). Once that happens I'll change it for Muscle Alpha also.