Form advantages:
Easy to learn.
They can indicate levels for setting stop losses and take profits.
They work on any markets, timeframes.
According to various studies, they give relatively accurate reversal signals.
In addition to Bulkowski's research, the Head and Shoulders pattern was analyzed by Gene Savin in 2007. He published his findings in the Journal of Financial Econometrics, and they confirm that the pattern has predictive value, but the author was unable to provide a theoretical explanation for why this pattern works.
Figure flaws:
Subjectivity. The figure is difficult to determine due to the fact that the market consists of many local tops and bottoms, and ideal patterns rarely appear. Sometimes the head and shoulders become visible when the reversal has already taken place.
Not all reversals fit into the shape of the Head and Shoulders pattern. If the Right Shoulder slightly exceeds the top of the Head (for example, forms an Upthrust), the pattern will “get confused”, but the market will not stop showing signs of weakness.