I appreciate your question but everyone's answer should be "both". Both have their place in certain missions and game types and both can be leveled up by the same warlock. In other words, there really is no reason to specifically pick one. (now you may play more as one Vs. the other, but since we haven't had any hands-on experience with the Sunsinger, I would say it's a bit early to pick a fave). Enjoy whatever you DO pick though!