Treat it with the upmost respect! Do not underestimate it at all. We pretty much have to treat ours like a hot since he is incredibly angry, rofl. Donnie took a hit off of him about a month ago. It bruised up pretty bad even though the bite didn't look too terrible. He said it hurt like all heck, and it hurt for a few days afterwards. They are extremely alert and prefer to bite first and ask questions later

They are rather territorial. Some will be fine once out of the cage, others are not. I think ours is bipolar, hehe.
With that said, there are those that are calm, but they are few and far between. They are an interesting species, their speed and strength is phenomenal... feeding response is awesome. Are you looking to get a northern or a southern?