It's an interesting concept. My immediate reaction is that it creates disincentives to work. In theory it does, but the only data we have is those who are currently on welfare and do not work -- but maybe those people were basically not going to work anyway! We have no competing group of people who are on welfare yet still CHOOSE to work to better their lives, because as soon as someone gets a job, no more benefits! So it's natural that an outsize chunk of people on public assistance don't work -- and the ones who stay on the longest, of course, don't WANT to work. But it undercounts those who go on the system then back out of it as they get work.
Other things that seem "obvious" to result: inflation. If everyone can afford $x for housing, why should housing costs not go up by a similar amount? The same way 2 incomes is now "normal", and the same way giving tax deductions on mortgage interest to make housing "more affordable" means, now that everyone can afford more housing, housing is bid up.
I don't know, but it's a fascinating experiment, anyone who is not paying for it should be in favor of this experiment -- unless you just hate poor people.