This is the most fun I've had with a game of this type since Call of Pripyat. I am blown away.
It's not flawless, but it does basically what Fallout 3 did, but miles better.
The simple fact that shooting things is actually satisfying makes the whole experience so much more enjoyable.
Base building isn't as deep as in dedicated crafting games like 7 Days to Die or what have you, but it's robust enough to be a nice diversion when you get tired of exploring.
Modding weapons is fun too, and I greatly appreciate the ability to give my guns stupid names.
Exteriors are vibrant and beautiful. Interiors are maybe a little too colorful and don't really capture the sense of decay the same as something like STALKER (or Fallout 3, I guess).
I am 100% on board with them eliminating weapon-specific skills and streamlining character progression, even though I know that isn't a popular opinion. It's nice to be able to play a game without being forced to limit yourself to only a few of the available items.
Dialogue and story are mediocre at best, but I really don't care about those things in a Bethesda game.
Treating the power armor as a limited "kill all the things" option is great IMO, and I like that it completely changes your HUD.
Inon Zur's score is literally the most Inon Zur score ever, to the point that I swear some parts are just direct samples from the Crysis soundtrack. I also swear I can hear some samples from the original FO1/FO2 soundtrack too, which is kind of cool. Also, there's a classical music radio station, which is great.
As a traditional RPG, it's "bleh." As a sandboxy explore and do whatever you want game, it's fantastic. Also, it's provided the singularly hilarious spectacle of Fallout 3 fans complaining about RPG mechanics being "dumbed down," as well as a wealth of entertainingly infuriating idiocy on the Steam forums (I saw several different people claiming that Bethesda developed Rage, Wolfenstein: The New Order, and New Vegas).
Navagon: So it's basically Borderlands with less guns, worse combat and fewer RPG elements?
No, not really at all.