Height doesn't matter much to me just so long as they are proportional. I like the heavy horses as long as they have the bones to carry the weight well. I'm getting to where I don't like QH anymore because most of them are bred for small feet and bones with too much muscling. That is why I fell in love with mustangs. Great feet, heavy bones, and solid muscles. Plus, they are more level headed than most. Dobe is about 15.2 hh and Koda is maybe 14.1 hh but both are solidly built. I do lots of cattle work and I couldn't do that with a skinny horse. Tall or short, the heavier the better in my mind.
I personally enjoy the taller horses better. I'm only 5'2 or so, but I've always ridden horses religiously that were at least 16hh. I'm helping train a quarter pony now, but I like the big horse's strides better.
I've had 14.2, 16.1, 15.3 stocky and 15.3 fine. I like 15.3 fine absolutely the best--this horse, anyway. He is long-strided at every gait, but I can mount more easily, reach the top of his back, my shortish legs fit around him. I'm crazy about him!
My Hanoverian is 17hh. I bought him sight unseen and got him home one night in December, two years ago. When he stepped off the three horse trailer, I thought I'd bought the whole darn barn. It took me six months to get on him cause I'm scared of heights. LOL! He was a rescue by the way. At the start of this riding season, I got on the shed roof to get on him, then progressed to the truck box and now my legs are flexible enough I only need a short stepladder, LOL!
My Pinto is 14.2hh, my Canadian is 15hh and my Standardbreds are 16hh and almost 16hh. Though all my horses stand still, my Pinto, Copper is the only one I never need an aide to mount from. Most of the time I have no difficulty with my Canadian.
So I guess 14.2 hh is what I prefer, LOL!