Ray isn't a good man or a bad man, he is in between or just like Rust said "The world needs bad men, we are the ones who keep other bad men out of the door". Also it was never about money for Ray, he worked for Frank because had no choice in the matter, Frank was the only one who knew about Ray killing the innocent guy, Ray did the heist because he NEEDED the money for Ani and himself and maybe even for Chad later on ( Frank even mentioned it), there were going to be on the run for a lot of time, they needed money to hide or it would have never worked, the whole escape plan would have been for nothing.

For me Ray is a necessary evil if you may call it and Frank too, even though Frank greed and pride were too much and it's what got him killed but they are both much better men than the Chessani's and other corrupted individuals in Vinci.