There's plenty of mileage in group decisions, and in the wisdom of crowds. I presume that, as technology enables the convening of groups, we'll see more decisions made collectively. I hope - and believe - that in general those decisions will be better.
However, making a decision is not the whole picture. There is a degree of responsibility that goes with a decision, and I'm coming to the conclusion that a group decision is worth nothing if the individuals in the group are not prepared to take individual responsibility for their decision.
One-line summary: watch out for decisions made by groups whose members are disengaged