the boy rides western, this was the first horse he ever rode on and about the third person who had had lessons on him. His owner, a real old school natural horsemanship trainer is a very good trainer so the horse knew it's stuff. However, this horse is one who also is a very good one to learn on because it's nature is to be the type of horse to constantly look for new games to win with the rider. The boy has had to learn quickly to stay ahead and in control of the horse. All in all he was perfect for the boy. The best thing I can compare this horse to is a decent natured teenager. Will try to test boundaries, find ways to be smarter, but ultimately will give if the right things are done. This one in particular was perfect for the boy but lousy for me. My weight tended to make him act a little muley when he got tired or was already tired. Just wouldn't go. He has a little bit of spook in him but I've never seen a horse that would try harder to stand his ground when he freaked. Don't think he would have a problem if I fell off him but have seen him stop on his own for the boy when the boy started to lose his seat while riding bareback. My 10 year old boy can also forcibly one reign stop him if he starts getting a little headstrong. Not sure he is big enough to do that with some of the cold bloods yet, but being a warm blood he seems a little more sensitive and quick to give even when upset.
Breeds do seem to have some personality characteristics that are unique to each one but it also depends on the horse. I've seen Paso s with all kinds of temperments, but mostly they seem fairly civil. I have noticed that some of them can kind of be like a lot of herding dogs. Kind of one owner animals. Intelligent, but not genius. Great horse to learn on, will make you pay attention until you get fundamentals down.
Transition of gaits is fairly easy for a experienced rider, little more challenging for a newby although the boy is doing well at it. I actually don't care for riding him very much, prefer my Peruvian but think he's a pretty good horse.
Mostly if you are really planning on getting one, either make sure you know how to feel him out yourself or take someone with you who is fairly experienced with this breed. I think they are decent horses, Have seen some real scary ones-mostly due to some real loser breeders around here. The few that I have known were very healthy. One caveat, they are a semi sensitive horse. If you are used to quarterhorses, Pasos are a little different emotional make up. I know there are different opinions on this board on training, natural vs old school vs pushing through/dominating. If you get one that has been "cowboyed" at some point. It does easily leave a mark on them and you might end up with a powderkeg that will go off when you least expect it. They are a little more like working with Arabians.
These are just my opinions, meant to be food for thought from my experience. There are a lot of people on here who have a whole lot more experience than I do and are much more qualified to give answers. I am by no means an expert and would recommend you doing a little more input seeking before taking my observations to deeply to heart.