To me the majority of them should overlap nicely, a small but strong and sound, dense boned work horse.
When you start to specialize, yup you may want to choose a QH to get down and cut a cow, you may
opt for the Arab to go do some dressage, but for just the general all around family horse that would try anything, go anywhere, and be fun doing it, either is good.
What wins it for me and makes my heart melt every time is when the girls go wide eyed, and the head and tail go up, and they start to float. To me that isn't spooky Arab, it is what Ace excels at, it's showing you stuff, just in case you missed the danger, if you see it and thank her for letting you know she is fine