None of them replaces a good workout outside but some times one can't go out.
That said, I have both a tranner and a roller. I personally like the roller better as I have a bad habit of getting into a mindless peddling thing with the tranner. Spin classes or LBS things are not an option for me because of location. I would think that a good spin class would be great if you have that option for keeping motivated. Reason I like the Roller better is that I have to keep my mind on what I am doing. I work on technique (blance peddle stroke ect.) more. But that is my personal opinion.
Dea