UBI is a difficult concept, since it’s hard to know how society will be distorted if it is implemented. There have been some small-scale experiments, but I don’t think that any experiment will truly capture the psychology of the populace until UBI is implemented on a wide scale.
On the one hand, people obviously respond to incentives. The incentive, when given a sum of money, is to work less. When everyone has this incentive, productivity will naturally take a hit and prices will go up to soak up the increased demand. That’s the downside.
On the other hand, some money will always be better than no money and people will be able to make better choices about their future with the knowledge that there’s a steady flow of money into their pockets (hello higher education). It will also alleviate the most severe cases of poverty in the nation, a massive upside.
All in all, the upsides to me clearly outweigh the downsides.