For most people, The Division 2 launches on Friday. But if you're crazy enough to spend close to $140, and you can download around 90GB fairly quickly, The Division 2 is playable now. To get an idea of what to expect, here's an hour from the early game.
Heather and Paul streamed just over an hour from the early section of the game on an Xbox One X. It's a good showcase of the difference in structure from the open beta - progress won't be anywhere near as fast, and you won't get a stupidly overpowered gun from the first mission.
But for the most part, the early missions are functionally the same. The major difference is that you've got access to a lot more toys - all the skills are unlocked now, as are all the side missions. That can affect how you approach the early game. I always like having a pulse to go with a turret, as opposed to the little RC drone, for instance.
I'll be getting hands on with The Division 2 later in the week, so we'll see how the servers stand up from a local point of view. For now, the word is they're holding up, which is a good sign.