What are your recommendations for the best, most accurate options demo accounts? I've been using TOS because of it's excellent strategy analyzer. However I've encountered several instances while using it to analyze butterflies and condors, where the prices of some of the spreads result in situations where there is no (or very little) possibility of loss on a trade. For example, a short butterfly with a very high risk/reward ratio, with the 'trench' nearly entirely above break even. I always ignore these anomalies and never use such trades when testing strategies, but they are disturbing and I would think not possible in actuality. Are there any demos out there that more accurately reflect true market pricing?