A given plant only has so much "potential". If you are able to keep your grow space dialed in and give your plant optimum conditions, the quality should be the same, whether grown indoors or out. However, outdoors will generally give you larger plants as sunlight is 360 degrees and you have all the fresh air you need. However, you can be subject to some undesireable conditions outdoors that you can control indoors, like humidity and the amount of water a plant receives. Thinks like weeks of rain, high humidity, high winds, wildlife, a cold snap, etc, etc, can ruin an outdoor grow. Like Rosebud said, 2 different animals, but that doesn't necessarily mean different quality.