"A horse may kick; but a mule aims."
I like that! So true, too
There wasn't much difference in my 2 mustangs than there has been in most of the young horses I've trained. Where the mustangs were a bit more flighty, they still reacted like a pretty typical horse. Dang mules, however, are just all around more difficult.
For example, when you are teaching a horse to break at the poll, you can just keep pressure until they break at the poll then release. You can wait until later in their training to work on getting them to back up with their neck tucked. A mule, however, you better keep hold of him until he backs up right from the start. If you let him get the idea that he can just tuck his nose and not move his feet, you'll have hell ever
getting him to go backward LOL.
There are a few thousand other little minute differences, but in my limited experience with mustangs, they generally reacted more like horses than mules.