Rainbow Boas get a bit larger than Ball's but not to the excessively long point. However, there are exceptions to that rule and my old Rainbow was just such an exception.
The unbelievable irredescent coloring and vibrant markings make the rainbow one of the prettiest snakes going that aren't "morphs". Another very docile specimin, although husbandry is a bit finickier with these as they require more specific temps and humidity in order to thrive. but, the end results are MORE than worth it!