回複：投資股票?

~20% annual return is good if it can do it over a long period.  I checked the link you provided about the system, its max peak-to-valley drawdown is 18.53% during Nov 02, 2011 to Nov 25, 2011.  The question to you is if you can bear such risk. If you have $200k invested in the system, for example, how do you feel about losing $37,000 in one month?  If the answer is yes, you can do it.  Otherwise, you stay away from it.