Looking at the last several thousand years of history, where is there any evidence of a civilization capable of managing such dangerous advanced technology?  Looking at the past several hundred years, and not ignoring the environmental catstrophe which is now our home planet, within what perspective of current society would managing such dangerous technology make any kind of universal sense.

When these questions can be answered satisfactorily without resorting to a completely controlled top-down society, only then can we begin to discuss the pluses and minus on the technology side.

From another angle, what's the point.  I for one have already decided, based upon the best evidence at hand, the only future which makes sense to me includes visions of happy children playing in a society powered by the source of life itself, the sun.  Measured against that vision, anything else smacks of the same blindness which has brought us to our current situation.

We are simply not evolved enough to manage anything other than the gentle power of the sun as it reaches us, for example, causing the temperature differences which bring us the wind.

"Life shrinks or expands in proportion to one's courage." - Anaïs Nin