Bloods are often nippy as babies, but usually settle down nicely as adults. They are generally quite talkative. You're right about the hissing, even while being totally relaxed. They just do that, but have very easy to read body language. For red bloods, the Bangka Island locality tends to be smaller, and they are quite clean, light pretty snakes.
If you're looking for examples of morphs, VPI has a nice photo gallery.
http://vpi.com/galleries