I found Utguard Keep to be a huge pain in the butt. I did not finish this instance till my whole group was 76-77. The first boss was easy sauce. It was the second pair of bosses that just kicked my butt. The melee guy could 2 shot any of my slaves with his charge, I could never keep agro on the caster guy even going full tilt on him. He would just stand there while my tank beat on him and just throw shadowbolts at my casters non stop like he wasnt even there.

I would say if you are going for xp. Nexus is your zone. Any and all of the bosses can be skipped, so if any one of them gives you fits like the caster lady you can just skip it. It also loops around so if your doing a trash xp run you end where you started, Not one of the specal gate opens only after the last boss dies shortcut that most zones use. Gundark or Violet Hold after that if Nexus dries up as you level. Culling of Stratholme too because its a lot of fun.