There's just SOO much to do in the game that most users will complete this game without even knowing 70% of the stuff that you can customise wrt to settlements etc. Also, as expected, it's a looong game if you're only going to put in 2-3 hours a day.
It delivers on pretty much everything if you've played 3 and were waiting for this game.
I was a little bummed out about the ending though, there maybe could've been some way to peacefully coexist with more than one faction. Anyhow, brilliant game nonetheless.