I've investigated Armstrong's stuff before and I would never trade based on it (after all, it was his attempts to trade based on his cycles which led to Princeton Economics going bust).
Having said that, it's really hard to fault his logic from a macro perspective. His general concept of cycles make a deal of sense, although I think his main mistake is hubris and believing that he can pin down these things to two decimal places (eg. 2008.22 or 2010.75).
Anyway, there are a lot of good "thinkers" about markets and patterns who get slotted because they try and extrapolate the logic into timing calls.
