Horizontal breakouts are much more reliable than diagonal breakouts. This is explainable in how humans think and act. Although I will not get into that here.
I posted here about Apple and Micron. These two will be used as an example.
Apple broke out of its symmetrical triangle. Its target is $140. But notice after the breakout that it just lingers around. This is typical of a symmetrical triangle. Sometimes it goes back into the apex. Other times it just grinds sideways for days.
Now look at Micron.
This is typical action for horizontal breakouts. This is especially true when the breakout is to an all time high or a high not seen in the past year or so. Micron begins to trend right to its target of $90.
When you trade futures you are trading very leveraged markets. Your losses and profits are magnified.
It is psychological torture for me to have the price linger around my entry point. This is a combination of two things. First, I am very impatient. Second, my stops are very tight. I risk very little money per trade. This gets me stopped out when trading diagonal breakouts.