A superficial cleanup is easier in a bathtub, but a tub, be it porcelain or fiberglass, holds blood evidence that can't be scrubbed away. And if you rinse the blood down the drain, you'll leave evidence in the drain trap.
No, best to do it the way Tony Soprano would ... in a butcher shop. Better tools, and the blood evidence is meaningless ... it is a butcher shop, after all.
That's right! My sister worked on a case in S. MS of two men who kill a third man, who had come in from out of town to do a drug deal. The man had brought his girlfriend along, and the other two held her hostage, and did other things to her, while they were torturing the guy. She heard them when they killed him, but they made the mistake of leaving the house for a while, and she was able to get free and get out of the house. The police were concerned about the lack of a body, or any evidence of a crime, but after talking with the girl, checked out the bathtub drain. Sure enough, there was evidence there. They'd taken the body in parts out to the bayou for nature to do it's work.
Needless to say, that woman needed some TALL therapy after that ordeal, but my sister said that when she showed up the following year for the trial, she was actually doing well.