I preordered and played beta and.. am still playing.
Most of the negative criticisms are true. It's buggy as hell and when they fix a thing they break 3 other things. They fix the bugs you like to take advantage of first before addressing the ones that prevent you from interacting in the world. There are massive stability issues and you DC a lot which is bad because most of the world building you are able to do in the game disappears when you log out. So in that sense it's pretty awful.
It does have some identity issues in that it's not sure if it's an MMO, PVP arena combat, or co-op. I get what they were doing in the design by creating the potential for real wasteland chaos, but i'm not sure it works in practice.
That said, the thing I enjoy most about Fallout games is exploration, carnanage, collection, repeat, and this game is all that. So I've been loving it through the frustration ands when I play, it's for hours at a time.
If they can fix it, it's gonna be a good game, but if you don't own it already, don't buy it until they do fix it.