Personally I think the game is pretty decent these days, just from a single-player perspective. From a value standpoint, you're probably better off buying the Fallout 4 GOTY edition, but if you're like me and you've played that to death then this is a good alternative.
The Wastelanders update added an actual story, and the recent Dawn of Steel (both free updates) expanded on that quite a bit. There seems to be no shortage of things to do in the game, and so far I've had a steady stream of constantly better gear and leveling up etc to do so I can survive more in increasingly dangerous areas. The music is fantastic, and starting with the Wastelanders update they actually added a great DJ into the mix.
If you're a Fallout fan, there are worse ways you could spend $16.