A high class SMG that you get for free (and even better, starts at lvl90 with 5 links when you get her now) providing well balanced stats, and a very powerful tanking skill. -Enemy ATK power (nevermind her own +evade!) that goes off in the first 3 seconds, makes tanking the initial contact much easier, and is usable even from an off-tank position.
Can easily be a main or off-tank, while she combos well with UMP45 defensively, lol in current year you don't even need UMP45 anymore (isn't it sad?). Her main weakness is she has very bad uptime (5/12) compared to some other SMGs, but the quick startup and utility (and the fact most fights are short anyway) make up for it.
Did I mention you get her at lvl90 and 5x linked? That's REALLY helpful if you're starting out. And did I mention she has an insanely broken mod? DEFINITELY pick her up.