I've gone through this, its all very easy. Basically nothing much changes apart from its a centralised dashboard that allows you to manage DEP and VPP as well as managed Apple ID's in one place.
The migration was fairly smooth. I freaked out at first because it appeared a good chunk of my devices were missing post-upgrade, but I just had to click the force sync button, and everything populated as expected. Haven't had any syncing issues since then.
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