All of the reasons already listed and I grew up with them. My grandfather started breeding QHs in the 50/60s with a son of Poco Dell, then also added in a son of Poco Tivio and a son of Poco Pine. My first mare of my own, I was 7, came straight off the King Ranch. I was on a QH before I was born and after I was born, I was riding before I could walk, literally. I've met & owned some that weren't the cakewalk stereotype but they have all been very cutting bred and true to that, they can be very sensitive and extremely responsive. With them you have to be a rider, never a passenger and always thinking 10 steps ahead of them.
I have to second the big butt opinion too. Love me a big, powerful hind end. My littlest cowpony at 9 months...I like big butts and I cannot lie... 0111.jpg
And Woodstock when he is fit makes me drooly. Right now he looks like a broodmare, he came through winter a bit fluffy. He had a major tendon/soft tissue injury and finally I can say he's been sound for a significant amount of time and will be back into boot camp after I'm back from vacation. Woodstockj.jpg