It seems that, apart from the cutting surfaces, the two models are very similar. As a general rule, prices are set according to supply and demand, but also depend on suppliers and availability of goods. As these can vary on a daily basis, a 'price trend' tool is available on each item's page to give a better idea of these fluctuations over the past few months. In this case, it seems that the price of the Smart Sileno City 600 is lower than usual. :)