Despite all that, his team pumps his opponents with regularity in shots, chances xG and goals. These are anecdotal observations that are skewing how you're evaluating these two players. They are VERY similar players that look different getting similar results. Fox may play more on the PK but his results are poor. It's one of the only real weaknesses in his game. McAvoy, on the other hand, is one of the best PK players on earth.
I just think people's eyes really lie to them a lot. Fox and McAvoy look really different on the ice. McAvoy is a physical specimen, he's loud on the defensive end of the ice and while he's graceful, there is a noiseyness to the way he plays the game. Fox is slick as hell and everything about his game is graceful. He's a quiet player who has a charismatic game. Depending on your perspective, you're going to draw conclusions based on your own biases as to who is "better" when really you're just saying which style you prefer.
That's why I like the data models so much. They don't give a shit what players look like. It takes all bias out of the equation and just tells you what happens. When you just look at what happens, these two guys look really similar and arguing which one you want seems silly.
I'll take McAvoy for the sole reason that they are the same age and Chuck has 1 more year on his deal. That's it. Don't think there is much differentiating either guy beyond that.