I normally redeem my FF miles when I fly back to China, but for business class tickets. A business class ticket normally can be exchanged with 90,000 miles (100,000 miles in Aeroplan case), while coach class ticket asks for 60,000 miles (75,000 miles for Aeroplan). But if you pay the ticket with money out of your pocket, a coach ticket will cost about C$1,500 and business class ticket about C$6,000. Comparably, getting a business class ticket with miles seems a great bargain. Of course the premise is that you should have accumulated enough miles for your spree.