I guess the biggest question with it is what is the differential in outcomes for people. What % of people who work now out of fear of living on the street would stop working if they could be sure they would have the bare minimum to survive. I can't imagine many. Everyone always wants more for themselves and their children. If people choose to not work, basic income puts a cap on how much of a "drain" they are on society.
There are a lot of nice properties to this concept and it would be interesting to hear well-founded opposition arguments. Unfortunately I have to assume that almost all of the arguments are going to be along the lines of "doing this will encourage people to be lazy" without any real evidence that this is the case.