I just watched the live broadcast. It's post-Strangetown, and one of the residents is Noelle Specter, descendant of Olivia. No aliens.
The rabbitholes are all portals with blue light, except for the Science Center, which is built around the rocket ship. The domes are all parks, each in memory of previous towns (Sunset Valley, Twinbrook, etc.) The only new content is a crystal tree that's pretty cool. There's some new furniture and new clothing.
It's nice to look at, but I plan to wait a bit. Right now, I'm looking forward more to Showtime.