I love the X Divider. I used it through all of the Normal difficulty FB Missions and it's my main online.
Edit: Something to note is that the X Divider cannot fly. If you dash in the air, the MS will also move towards the ground. That being said it's pretty fast for a 2500 suit and along with it's godly machine gun, you can keep up pressure easily. CSB is once per life but the G-Bits track the enemy until the moment they fire which can be used for interception if you get caught in a melee combo moments after you let go of the button.
Also as an easter egg, if you finish the fight with either CSB or the Burst Attack, your victory pose will be in X form, not X Divider.