Not for the amount of time I spent travelling on those lines, no. It made for a nice, comfy journey on the NEX and Shinkansen, but the normal pass would have gotten me a reserved seat too. As I mentioned, other than that, I spent almost all my time travelling on lines without green cars, making the benefit of dubious value.

Of course, if the op is travelling on lines which are served by trains with green cars, that's a different story ...