There's two issues that I don't think have been adequately addressed, or that I missed, in the banter over this issue. 1) What would stop us from recreating the inefficient welfare state that already exists on top of this new one when some people inevitably blow their UBI on drugs/cheetos/whatever and don't have money for rent? It seems that for this to work we'd have to maintain some intestinal fortitude to say "no"…
I'd argue that the culture is currently overwhelmingly biased toward saying "no," usually under the guise of "freedom" -- if we couldn't say "no" to the chronically homeless, we probably wouldn't have a half-million of them on the streets. If we couldn't say "no" to low-income mothers, we wouldn't have the highest maternal mortality rate in the developed world.