I find that outdoor if allowed to fully mature is definitely better than anything grown indoors. Indoor weed tends to taste better because it is usually fresher and because of the controlled environment you can realy give it all it needs.
I have had really excellent indoor weed in both taste and quality but it never quite reaches the quality of a properly timed harvested and cured outdoor grow.
Also some people say that outdoor is more sustainable, actually soil farming is one of the most unsustainable techniques to be used. If all our food be grown in soil we would need a size of south america to feed us all. Hydro is the way to go both for food and for cannabis in my opinion.