They get to be 5.5 to 8 feet, gender being the biggest factor, around 3 inches in diameter at their widest. My 3 1/2 year old male is 7'8" and weighs just under 11 pounds.

If by "nippy" you mean repeated striking that makes them a pain to handle, then no. They'll occasionally strike by mistake when they're about to be fed or have just been fed, but a few precautions can prevent this. They are touchy and sometimes aggressive when in shed, during which mine (who rarely bites) twice tagged me as a juvenile. They have a reputation for this, but it probably varies with the animal.

Other than that they are amenable to handling and very docile.