I raised and bred a pair of lucy Texas rats and all they did was try to bite, despite frequent handling. They came from different breeders. Once they got to 4 feet, there were somewhat better as far as temperment, but I sold them because I was sick of them striking at me.
I have also raised and bred albino black rats. They were great snakes. They would sometimes go into "strike position" when I reached into their cage, but once picked up, they were fine. I think black rats may be my favorite snakes, but I no longer keep them due to a retarded ODNR ruling that requires they be PIT tagging, inspections, and annual fees being paid (I live in Ohio and even captive bred color morphs fall under this regulation).
I also disagree with the post that Texas rat snakes get bigger than black rats - the record size for a black rat is 101 inches - that's over eight feet long.
Tim