I've been a user of DeMark indicators for 10+ years and have found them to be quite powerful. Granted, they can be tricky to interpret and it's taken me years to grow comfortable with their nuances. But nothing is the "Holy Grail," meaning one should never put too much emphasis on any one indicator, instead preferring to use a suite of uncorrelated tools to help make decisions.
That said Mr. DeMark has made many prescient calls over the years, the latest being his call in December for China's Shanghai index to rally -- not bad! I respect his calls, however I still believe risk-on remains the prevailing market bias for the near future. As I wrote previously, the YTD rally came with extended and robust momentum, which typically has carry-through in the form of thrust. I'm not saying 1567 won't be a top, it could very well be, assuming we get there. But fortunately tops take time to form, in contrast with more fast-and-furious declines to bottoms, and as such I believe we'll have time to assess things over the next few weeks and make a decision then if indeed the market is acting as if a top is in.
In the meantime, I show below three SPY charts which I feel support what Tom is considering in his market call. He particularly highlighted that when 13 signals register across all three time frames (daily, weekly, monthly), it has been very powerful.