I have a Morgan. Very sweet but loves to test you (not in a mean way, more of an I don't "feel" like doing that, can I get away with quietly refusing).
A bit high-strung and a go, go, go kind of guy which I have been told is typical for the breed. Loves to learn new things and doesn't get upset even if you have no clue what you are doing or he has no idea what you are asking him to do. The trainer I bought him from was successfully using him as a lesson horse for teens and he was a very green 4yr old at the time.