The carpet python may be nippy (many arboreal snakes are). Also, they usually do not like being handled and will be moving constantly. The Rainbow boa is not a beginner snake. Rainbows require higher humidity. A Hog (not Hogg) Island boa is the way to go. They can be a little nippy and hissy when small, but usually mellow out with regular handling. You may get bitten. Remember to always let the snake know you are picking him/her up. Do not reach for the face. That's a bite. Do not have any odor on your hands (i.e. rodents, cat, dog, etc). That's a bite. Keep the snake away from your face. Sometimes they will pick up the intense heat coming from your nose and mouth and nail you. Hope this helps and get the Hog.
Phil Goss