This topic seems to be controversial as the topic whether god exists or not. Some guys at Cambridge doing research on this topic. It is funny to see they said TA didn't work in one paper and then later they said it had values! But it is strange that few people aruge FA works or not. Does FA sure work?
Does TA/FA works? The answer can't be sharp, it oscillates somewhere around the middle. I can also respond: "It depends"
From all the people that I have met, many of them (esp the academic) always suspect the value of TA. But they don't ask the value of FA. It seems they all believe FA works.
When you look at CTAs & hedge funds performance indicies (adjusted for survivorship bias) you'll see positive returns. As far as I know, majority of these managers use TA and FA or some related methods. There is also "statistically significant persistence" in their performance. See: http://www.mfainfo.org/news/pr/5-27-98.htm So, if you ask "does TA/FA work?" - the answer should be placed between yes and no, but closer to YES, IMHO. Of course, we can always speak only about the past...