there really is no specific difference. Usually, and I say usually, because there are exceptions, indoor is usually more potent than outdoor. Only because you can totally control all of the aspects of your grow. Outdoor grown typically tastes and burns better than indoor b/c it is usually all organically grown in soil with natural ferts, whereas and indoor hydro setup normally uses chemical ferts and if they arent flushed completely before harvest than they can taste and smell off. Sometimes they even spark b/c of too much nitrogen still in the bud.