Pitching Data - How do you Evaluate?

So, we have three stats: Arm, Stuff, and Control.

I figure it as this:

Arm - how quickly ball gets to catcher results in how quickly we can react

Stuff - how deceptive the pitches are results in us humans confused as to whether it's a ball or a strike

Control - ***** vs strikes results in how much 'guessing' we need to do as humans.

But importantly..what do you value most? So many pitchers are like 9-1-9 or 8-8-2. Very few are 5-7-6 - meaning they are great in one area and not another.

I'm not sure who or what I should choose when bringing in a pitcher. On one hand, a fast pitch means everyone has to react quicker. But better stuff seems confuse the player more. I almost want low 'control' because with good 'stuff' - hitter has to try and hit everything. I've also noticed (or am I wrong..sometimes a 100mph fast ball doesn't seem as fast as an 85mph fast ball).

So, I may have answered my question to a degree. I feel like if it was just the computer playing the computer, the answer might be different. Or do these ratings affect how the computer calculates your ability to get a hit off of a pitch? I don't seem to see it more difficult to hit off a good pitcher vs. a bad one.