All the proposals I've seen emphasize the basic nature of it, meaning people would just barely be able to survive. The key difference, to me, between welfare and UBI is that welfare, in it's current form, punishes people for trying to obtain extra income. A UBI, I think, could potentially free people up to do work they love that is the most meaningful to them and, potentially, more meaningful to society.

I'm not completely sold on it yet, but I do think it's a very interesting idea and, as you said, I think it's coming regardless of what I think about it.