After six hours of play:
First impressions are very good. It's a difficult game to stop playing for sure. The music and graphics create a great atmosphere. It does a very good job at portraying you as a new player on the galactic exploration scene, eager to learn as much as you can about the universe around you. Gameplay is fun, too.
Overall, it's very fun, and shows great promise. Can't wait to play it MP with siblings and friends.
At the same time... I'm looking forward to it being improved by patches and DLCs. It doesn't have the depth and functionality of Europa Universalis 4, and doesn't feel quite as immersing. As fun as anomalies are, sending research ships on endless survey missions does get a bit tedious after a while.
My #1 wishlist item right now is all the functionality that's in EU4, such as a message log, ledger, more exhaustive outliner, etc.