Have you used MM as well Pad?
I follow MM, but view it more as an overlay of how the market is going, ie an interpretation of the market rather than a trading system for the market. In the end of the day the market is of course the only truth and there are many ways of looking at it.
Is it useful to me? Yes at times it highlights time periods where the mkt almost has to turn at a certain degree. It tends to gel with concepts i follow, ie patterns, waves, fibonacci etc but i wouldn't view it as a trading system per se, more a background understanding in a market in which one applies trading systems.
In the end though I think one gets to the point where there is just a market and you've looked at it long anough to get a feel for what is happening. Whether one gets there with indicators, patterns, EW, commercial trend following, breakout or counter trend systems I don't think matters too much. I would say matrix as a bundle of techniques highlights areas in time and price for turns, but price wise I have my own approaches for that for my day to day intraday trading. It has informed me on my journey I guess. Like all else in trading it is no holy grail as that is inside us.
I have struggled with the idea of swing trading which is why I was interested in nexus. I answered as I saw the thread and have just got the book.
To me backtesting looks OK, and to be fair in the book it is demonstrated from Oct to mid april showing every entry. My testing since jan last year to today suggests the results are replicable over a longer period but need longer and need the live entries to see how it performs after commissions, slippage, paddington error etc etc
cheers
P