The only downside for now is that "they aren’t a true all-in-one sneaker. They just aren’t meant for a run". But Wired still rated them 9/10.
Seems like an interesting buy, especially for this summer. Looks like acceptable slippers for the office :p
http://www.wired.com/2016/03/review-allbirds-wool-runners/
http://www.wired.com/2016/03/review-allbirds-wool-runners/