Basically lease options are heavy favorites for the sellers. It is a good way to make money because the odds are VERY substantial that the buyer does not exercise the option. Similarly there are always complexities with the pricing and appraisal valuation because none of them can be really decided until the option is exercised. If the seller is smart they will structure the option to be open ended in such a way that they can price accordingly for an appreciating market yet keep the pricing static for a depreciating market. So you as the buyer need to make sure that the option is structured in such a way as to minimize your risk of loss of the option price including events that will happen due to appraisal or not making appraisal.